BrowserSiftTechnical edition

BrowserSift demo fixture page (local only)

Target http://fixture.browsersift.internal/scan · Created 2026-10-13T07:55:54.844Z · Technical edition

4 finding(s), 1 high priority. Execution completed is not a pass.

Actual issues found

including 1 high priority

Engine coverage

3/3

engines executed of those planned — executed, not passed

Main content visible (LCP)

36–120 ms

Time until the main content becomes visible (LCP)

Full page load

56–146 ms

Time until the full page finishes loading (load event)

Measured speedMain content became visible in 36 ms on the fastest completed engine and 120 ms on the slowest (84 ms spread, single local sample). This is one local, unthrottled sample — not a production-user speed rating.

Priority findings

Overview

#	Finding	Severity	Engines	First proposed action (UNVERIFIED)
1	JavaScript error thrown on page interaction	high	Chromium, Firefox, WebKit	Define or import the missing function before it is invoked. (unverified)
2	Horizontal page overflow at 1440px viewport	medium	Chromium, Firefox, WebKit	Use max-width or a responsive width instead of a fixed 1800px. (unverified)
3	Vue runtime warning or error observed	medium	Chromium, Firefox, WebKit	Fix or define the referenced method on the component. (unverified)
4	WebAssembly module failed to load, compile, link, or run	medium	Chromium, Firefox, WebKit	Confirm the .wasm artifact is served with the application/wasm MIME type. (unverified)

Measured overview

Load milestones by engine (absolute nav-origin times)Captured report data · see scope below

Full caption & source

Each marker is an actual measured milestone at its absolute time from navigation start — this is NOT a stacked duration chart. Coincident milestones share a position; hover for the exact label. Source: this report's current recorded run (initial observation window); no remote images or script output. Offline copy: hover and selection are unavailable; use the numeric table for exact values.

Numeric data — Load milestones by engine (absolute nav-origin times)

Engine	Milestone	ms
Chromium	TTFB	2.4
Chromium	FCP	36
Chromium	LCP	36
Chromium	DCL	132.7
Chromium	load	132.8
Firefox	TTFB	24
Firefox	FCP	120
Firefox	LCP	120
Firefox	DCL	146
Firefox	load	146
WebKit	TTFB	4
WebKit	FCP	57
WebKit	LCP	57
WebKit	DCL	55
WebKit	load	56

Diagnostics by category and engineCaptured report data · see scope below

Full caption & source

Actual observed diagnostic counts per completed engine, stacked by category. Translucent segments are policy-aborted entries caused by our own same-origin policy — they are shown separately, not as site errors. Source: this report's current recorded run (initial observation window); no remote images or script output. Offline copy: hover and selection are unavailable; use the numeric table for exact values.

Numeric data — Diagnostics by category and engine

category	Chromium site	Firefox site	WebKit site
javascript	1	1	1
vue	2	2	2
wasm	1	1	1

Findings × engine coverageCaptured report data · see scope below

Full caption & source

Teal = issue observed on that engine; grey = no observation on that engine (not a pass); blank = not collected. Severity is shown in the findings list. Source: this report's current recorded run (initial observation window); no remote images or script output. Offline copy: hover and selection are unavailable; use the numeric table for exact values.

Numeric data — Findings × engine coverage

Finding	Chromium	Firefox	WebKit
JavaScript error thrown on page interaction	observed	observed	observed
Horizontal page overflow at 1440px viewport	observed	observed	observed
Vue runtime warning/error	observed	observed	observed
Wasm load/compile failure	observed	observed	observed

Resource bytes by initiator type — ChromiumCaptured report data · see scope below

Full caption & source

Known transfer sizes only. 0 resource(s) had unknown size and are excluded — this ring is not full page weight. Source: this report's current recorded run (initial observation window); no remote images or script output. Offline copy: hover and selection are unavailable; use the numeric table for exact values.

Numeric data — Resource bytes by initiator type — Chromium

initiatorType	bytes	unknownSizeCount
script	599158	0
link	514	0

Resource bytes by initiator type — FirefoxCaptured report data · see scope below

Full caption & source

Numeric data — Resource bytes by initiator type — Firefox

initiatorType	bytes	unknownSizeCount
script	599158	0
link	514	0
other	0	0

Resource bytes by initiator type — WebKitCaptured report data · see scope below

Full caption & source

Numeric data — Resource bytes by initiator type — WebKit

initiatorType	bytes	unknownSizeCount
script	599158	0
link	514	0

Technical charts

LCP by engine (ms)Captured report data · see scope below

Full caption & source

Actual measured values, same unit on one axis. A null means the metric was not collected on that engine — shown as an explicit gap, never zero. Single local samples, not production speed. Source: this report's current recorded run (initial observation window); no remote images or script output. Offline copy: hover and selection are unavailable; use the numeric table for exact values.

Numeric data — LCP by engine (ms)

Engine	LCP
Chromium	36
Firefox	120
WebKit	57

Resource waterfall — ChromiumCaptured report data · see scope below

Full caption & source

Actual captured resources in receipt order on a shared nav-origin ms axis covering every reported resource and milestone; filtering does not rescale the axis. DNS blue · TCP purple · TLS violet · wait amber · download green. Legacy entries without detailed timings are a single duration bar — no phases are invented. Milestone marks are labelled FCP/LCP/DCL/load. Source: this report's current recorded run (initial observation window); no remote images or script output. Offline copy: hover and selection are unavailable; use the numeric table for exact values.

Numeric data — Resource waterfall — Chromium

Resource	Start ms	End ms	Transfer	Phases
/static/style.css	6	12	514	duration only
/static/vue.global.js	6	90	596715	duration only
/static/app.js	7	13	2443	duration only

Load events — ChromiumCaptured report data · see scope below

Full caption & source

Actual measured phases, long-task spans, layout-shift points and LCP candidates on one shared nav-origin time axis. Lanes without event arrays (unsupported or legacy report) are Not collected — not observed-empty. No CPU-utilization, flamegraph, TBT or filmstrip claims are made. Source: this report's current recorded run (initial observation window); no remote images or script output. Offline copy: hover and selection are unavailable; use the numeric table for exact values.

Numeric data — Load events — Chromium

Event	atMs	detail
TTFB	2.4	Not collected
FCP	36	Not collected
LCP	36	Not collected
DCL	132.7	Not collected
load	132.8	Not collected

Resource waterfall — FirefoxCaptured report data · see scope below

Full caption & source

Numeric data — Resource waterfall — Firefox

Resource	Start ms	End ms	Transfer	Phases
/static/style.css	61	98	514	duration only
/static/vue.global.js	62	100	596715	duration only
/static/app.js	62	100	2443	duration only

Load events — FirefoxCaptured report data · see scope below

Full caption & source

Numeric data — Load events — Firefox

Event	atMs	detail
TTFB	24	Not collected
FCP	120	Not collected
LCP	120	Not collected
DCL	146	Not collected
load	146	Not collected

Resource waterfall — WebKitCaptured report data · see scope below

Full caption & source

Numeric data — Resource waterfall — WebKit

Resource	Start ms	End ms	Transfer	Phases
/static/style.css	13	14	514	duration only
/static/vue.global.js	14	18	596715	duration only
/static/app.js	17	19	2443	duration only

Load events — WebKitCaptured report data · see scope below

Full caption & source

Numeric data — Load events — WebKit

Event	atMs	detail
TTFB	4	Not collected
FCP	57	Not collected
LCP	57	Not collected
DCL	55	Not collected
load	56	Not collected

Engines checked

Chromium

156.0.8078.4

completed

TTFB2 ms
First contentful paint36 ms
Largest contentful paint36 ms
Full page load133 ms
DOM content loaded133 ms
Cumulative layout shift0.001

TTFB, paint and load values are independent observations from one initial-load sample, not additive phases. No performance score is computed.

Firefox

157.0

completed

TTFB24 ms
First contentful paint120 ms
Largest contentful paint120 ms
Full page load146 ms
DOM content loaded146 ms
Cumulative layout shiftNot collected

TTFB, paint and load values are independent observations from one initial-load sample, not additive phases. No performance score is computed.

WebKit

27.2

completed

TTFB4 ms
First contentful paint57 ms
Largest contentful paint57 ms
Full page load56 ms
DOM content loaded55 ms
Cumulative layout shiftNot collected

TTFB, paint and load values are independent observations from one initial-load sample, not additive phases. No performance score is computed.

Report details & scope

Report ID:: recorded-demo-20261013
Target:: BrowserSift demo fixture page (local only)
URL:: http://fixture.browsersift.internal/scan
Created:: 2026-10-13T07:55:54.844Z
Elapsed:: 17 s
Mode:: Live run
Scope:: Recorded demo scan of the fixed local fixture page including the signed-in (protected) area with the published demo account. External public URL scanning is not available.
Offline note:: Offline HTML export: screenshots and other private evidence files are not embedded; only their metadata and hashes are listed. Open the live report while signed in to view them.

Assessment

4 finding(s), 1 high priority. Execution completed is not a pass.

Coverage

Planned: Chromium, Firefox, WebKit · Completed: Chromium, Firefox, WebKit

Browser runs

Engine	Version	Platform	Viewport	Status	Started	Finished	Duration	Error
`chromium` Chromium	156.0.8078.4	win32-x64	1440×900	completed	2026-10-13T07:55:38.314Z	2026-10-13T07:55:42.917Z	4.6 s	—
`firefox` Firefox	157.0	win32-x64	1440×900	completed	2026-10-13T07:55:42.978Z	2026-10-13T07:55:49.263Z	6.3 s	—
`webkit` WebKit	27.2	win32-x64	1440×900	completed	2026-10-13T07:55:49.674Z	2026-10-13T07:55:54.792Z	5.1 s	—

Analysis context

Analysis context — Chromium

Actual browser version: 156.0.8078.4

Technology	Family	Version	Version source
vue	framework	3.5.43	public Vue.version
wasm	runtime	Unknown (version could not be read)	Unknown

Rendering probe (bounded sample): canvas sampled 0; DOM elements inspected 18; probe hit node cap and stopped early: no; count scope: inspected-elements (max 30). These counts describe the bounded probe window only, not page-wide totals.

Source mapping: generated-only — generated/bundled positions only; no original component source is mapped. Collection time: 4 ms.

generic-runtime-v1 revision 1 — focus: general JavaScript runtime and network diagnostics (Baseline adapter always selected)
vue-component-v1 revision 1 — focus: application stack framing, handler warning context (Vue observed via public markers)
wasm-module-v1 revision 1 — focus: module response MIME and status, import/runtime cause distinction (Actual wasm module resource observed)

Profile limitations:

Markers are evidence-only; absence does not prove a technology is not used.
Adapter strategies are declared, not executed; no source-map or original mapping was performed.
Wasm module/toolchain version is explicitly unknown; no version is fabricated.
Rendering counts cover only the bounded probe window of 30 inspected elements; they are sampled observations, not full-page totals.

Observed platform-profile JSON artifact is not present in this report, so it cannot be referenced.

Analysis context — Firefox

Actual browser version: 157.0

Technology	Family	Version	Version source
vue	framework	3.5.43	public Vue.version
wasm	runtime	Unknown (version could not be read)	Unknown

Source mapping: generated-only — generated/bundled positions only; no original component source is mapped. Collection time: 4 ms.

generic-runtime-v1 revision 1 — focus: general JavaScript runtime and network diagnostics (Baseline adapter always selected)
vue-component-v1 revision 1 — focus: application stack framing, handler warning context (Vue observed via public markers)
wasm-module-v1 revision 1 — focus: module response MIME and status, import/runtime cause distinction (Actual wasm module resource observed)

Profile limitations:

Markers are evidence-only; absence does not prove a technology is not used.
Adapter strategies are declared, not executed; no source-map or original mapping was performed.
Wasm module/toolchain version is explicitly unknown; no version is fabricated.
Rendering counts cover only the bounded probe window of 30 inspected elements; they are sampled observations, not full-page totals.

Observed platform-profile JSON artifact is not present in this report, so it cannot be referenced.

Analysis context — WebKit

Actual browser version: 27.2

Technology	Family	Version	Version source
vue	framework	3.5.43	public Vue.version
wasm	runtime	Unknown (version could not be read)	Unknown

Source mapping: generated-only — generated/bundled positions only; no original component source is mapped. Collection time: 4 ms.

generic-runtime-v1 revision 1 — focus: general JavaScript runtime and network diagnostics (Baseline adapter always selected)
vue-component-v1 revision 1 — focus: application stack framing, handler warning context (Vue observed via public markers)
wasm-module-v1 revision 1 — focus: module response MIME and status, import/runtime cause distinction (Actual wasm module resource observed)

Profile limitations:

Markers are evidence-only; absence does not prove a technology is not used.
Adapter strategies are declared, not executed; no source-map or original mapping was performed.
Wasm module/toolchain version is explicitly unknown; no version is fabricated.
Rendering counts cover only the bounded probe window of 30 inspected elements; they are sampled observations, not full-page totals.

Observed platform-profile JSON artifact is not present in this report, so it cannot be referenced.

Version experience (owner-scoped historical reference)

Version experience: no owner-scoped prior reference is available for this report's findings.

Findings (all, independent of any UI filter)

highFunctionality and interaction

JavaScript error thrown on page interaction

Confidence probable · engines Chromium, Firefox, WebKit · signature js-error/page-interaction

Observed:

chromium (156.0.8078.4): [pageerror] ReferenceError: undefinedHelper is not defined at app.js:7:9 | firefox (157.0): [pageerror] ReferenceError: undefinedHelper is not defined at app.js:7:9 | webkit (27.2): [pageerror] ReferenceError: Can't find variable: undefinedHelper at app.js:7:24

Expected: The demo button should trigger its handler without throwing an uncaught error.

Generated source locations: fixture:/static/app.js:7:9; fixture:/static/app.js:7:24

Reproduction:

Open the demo fixture page in any listed engine.
Click the 'Trigger demo error' button.
Open DevTools console and observe the uncaught ReferenceError.

Suspected causes (with uncertainty):

Fixture code calls undefinedHelper() which is not defined anywhere in the page. (uncertainty: We have not verified intent; this is intentionally planted for the demo. On a real site the cause would need source review.)

Proposed actions:

Define or import the missing function before it is invoked.
Wrap third-party integrations in try/catch and log via a reporting hook.

Validation:

Reload the page and click the same button.
Confirm the console shows no uncaught errors.

Limitations:

Single-run observation: confidence stays 'probable' until a separate repeated run validates the same error reproduces.
Grouped across engines: shared issues are not proof of an engine-specific defect.

Rule-based observation; no source-level cause asserted

mediumLayout and display

Horizontal page overflow at 1440px viewport

Confidence probable · engines Chromium, Firefox, WebKit · signature layout/horizontal-overflow-1800px

Observed:

chromium: scrollWidth=1850px at innerWidth=1440px; firefox: scrollWidth=1850px at innerWidth=1440px; webkit: scrollWidth=1850px at innerWidth=1440px

Expected: Content should fit the viewport width (no horizontal scroll at 1440px).

Reproduction:

Open the demo fixture page at a 1440x900 viewport.
Observe the horizontal scrollbar caused by the 1800px-wide .overflow-box element.

Suspected causes (with uncertainty):

A fixed pixel width (1800px) on .overflow-box exceeds the 1440px viewport. (uncertainty: On a real site the specific culprit element and stylesheet source would need DOM inspection.)

Proposed actions:

Use max-width or a responsive width instead of a fixed 1800px.
Add overflow-x handling or container queries where fixed widths are required.

Validation:

Reload at 1440x900 and confirm document.scrollWidth <= window.innerWidth.

Limitations:

Single-run measurement; a repeated run is required to upgrade confidence.
Shared across engines: this is not evidence of engine-specific behaviour.

Rule-based diagnosis

mediumFunctionality and interaction

Vue runtime warning or error observed

Confidence probable · engines Chromium, Firefox, WebKit · signature vue/runtime-warning-or-error

Observed:

All engines: [Vue warn]: Unhandled error during execution of native event handler + TypeError: this.notDefinedOnPurpose is not a function

Expected: The Vue application should run without runtime warnings or uncaught handler errors.

Short title: Vue runtime warning/error

User impact (rule): Interactive parts of the page can stop working for visitors when this error happens.

Generated source locations: fixture:/static/vue.global.js:2446:15; fixture:/static/app.js:20:25

Reproduction:

Open the demo fixture page.
Click the 'Trigger demo Vue error' button.
Observe the Vue runtime warning and the handler error in the console.

Suspected causes (with uncertainty):

A Vue event handler dependency (method or bound property) appears missing or not callable at call time. (uncertainty: Classification is based on the actual runtime message; the original .vue component cannot be mapped because no public source map is available.)

Proposed actions:

Fix or define the referenced method on the component.
Add an app-level errorHandler to surface uncaught handler errors.

Validation:

Reload and repeat the interaction; confirm no [Vue Warn] or handler error appears.

Limitations:

Generated bundle file/line/column only; original .vue source mapping is unavailable (no source map).
Vue detection itself is evidence-only and not reported as a defect.

Rule-based observation

mediumResource loading

WebAssembly module failed to load, compile, link, or run

Confidence probable · engines Chromium, Firefox, WebKit · signature wasm/streaming-failure

Observed:

chromium: Incorrect response MIME type. Expected 'application/wasm'. | firefox: Response has unsupported MIME type 'application/octet-stream' expected 'application/wasm' | webkit: Unexpected response MIME type. Expected 'application/wasm'

Expected: The wasm module should compile, link, and run without errors; streaming responses should use application/wasm.

Short title: Wasm load/compile failure

User impact (rule): Features built on WebAssembly may silently fail to load for visitors.

Reproduction:

Open the demo fixture page.
Click the 'Trigger demo Wasm load' button.
Observe the failure reported in the console.

Suspected causes (with uncertainty):

A streaming compilation failure was observed, and the observed content-type did not match application/wasm. (uncertainty: Engine-specific wording differs; the exact cause of the streaming failure is classified from the actual error message.)

Proposed actions:

Confirm the .wasm artifact is served with the application/wasm MIME type.
Verify the module's import/export table matches the host object (link errors).

Validation:

Re-run with the specific cause addressed and confirm no wasm error appears.

Limitations:

Failure kind is taken from the actual error message; no invented scoring.
WebAssembly capability itself is evidence-only and not a defect.

Rule-based diagnosis

Performance — chromium

Sample	1 (authenticated context (actual sample cache mode; auto-login succeeded for this engine), local unthrottled, initial load)
TTFB	2 ms
DOMContentLoaded	133 ms
Load	133 ms
First Contentful Paint	36 ms
Largest Contentful Paint (observation-limited)	36 ms
Cumulative Layout Shift (observation-limited)	0.001
Long tasks	0
Long task total	0 ms
Observed entry types	largest-contentful-paint, layout-shift, longtask, element, event, first-input, interaction-contentful-paint, long-animation-frame, mark, measure, navigation, paint, resource, soft-navigation, visibility-state
Observation window	1517 ms

Performance values are from a SINGLE authenticated-context context, local unthrottled initial load per engine. They are not production-user metrics, not field data, and a single sample is not a reliable speed ranking. LCP/CLS are observation-window-limited. No Lighthouse score, INP or p75 is computed. Unsupported metrics are shown as Not collected and are never substituted with zero.

Resource waterfall — chromium (3 of initial-load window; later interaction resources excluded)

Start ms	Duration ms	Initiator	URL (redacted)	Status	MIME	Transfer B	Download ms
6.1	5.4	link	fixture:/static/style.css	200	text/css	514	0.2
6.4	83.8	script	fixture:/static/vue.global.js	200	text/javascript	596715	0.5
6.5	6.3	script	fixture:/static/app.js	200	text/javascript	2443	0.3

Unknown sizes/phases are shown as unknown/—, never as zero.

Diagnostics — chromium

error · problem type: Functionality and interaction · signal source: javascript · pageerror

ReferenceError: undefinedHelper is not defined
    at HTMLButtonElement.<anonymous> (http://[redacted]:57149/static/app.js:7:9)

Location: fixture:/static/app.js:7:9 (generated/bundled position)

Observation phase: click-js-demo - Observed at: 1702 ms (navigation-relative). These describe when the diagnostic was observed, not its cause.

warning · problem type: Functionality and interaction · signal source: vue · console

[Vue warn]: Unhandled error during execution of native event handler 
  at <App>

Location: fixture:/static/vue.global.js:2446:15 (generated/bundled position)

Observation phase: click-vue-demo - Observed at: 2249 ms (navigation-relative). These describe when the diagnostic was observed, not its cause.

error · problem type: Functionality and interaction · signal source: vue · pageerror

TypeError: this.notDefinedOnPurpose is not a function
    at Proxy.boom (http://[redacted]:57149/static/app.js:20:25)
    at callWithErrorHandling (http://[redacted]:57149/static/vue.global.js:2593:21)
    at callWithAsyncErrorHandling (http://[redacted]:57149/static/vue.global.js:2600:19)
    at HTMLButtonElement.invoker (http://[redacted]:57149/static/vue.global.js:11857:9)

Location: fixture:/static/app.js:20:25 (generated/bundled position)

Observation phase: click-vue-demo - Observed at: 2250 ms (navigation-relative). These describe when the diagnostic was observed, not its cause.

error · problem type: Resource loading · signal source: wasm · console

[demo wasm] instantiateStreaming failed: Failed to execute 'compile' on 'WebAssembly': Incorrect response MIME type. Expected 'application/wasm'.

Location: fixture:/static/app.js:39:19 (generated/bundled position)

Observation phase: click-wasm-demo - Observed at: 2814 ms (navigation-relative). These describe when the diagnostic was observed, not its cause.

Capability signals (evidence only, not a defect list): Vue detected=true (window.Vue global present; __vue_app__ marker on #vue-app; [Vue warn]: Unhandled error during execution of native event handler at <App>); Wasm supported=true, streaming=true, wasm resource seen=true; failures: streaming-mime: [demo wasm] instantiateStreaming failed: Failed to execute 'compile' on 'WebAssembly': Incorrect response MIME type. Expected 'application/wasm'..

Performance — firefox

Sample	1 (authenticated context (actual sample cache mode; auto-login succeeded for this engine), local unthrottled, initial load)
TTFB	24 ms
DOMContentLoaded	146 ms
Load	146 ms
First Contentful Paint	120 ms
Largest Contentful Paint (observation-limited)	120 ms
Cumulative Layout Shift (observation-limited)	Not collected
Long tasks	Not collected
Long task total	Not collected
Observed entry types	largest-contentful-paint, event, first-input, mark, measure, navigation, paint, resource
Observation window	1517 ms

Resource waterfall — firefox (4 of initial-load window; later interaction resources excluded)

Start ms	Duration ms	Initiator	URL (redacted)	Status	MIME	Transfer B
61	37	link	fixture:/static/style.css	200	text/css	514
62	38	script	fixture:/static/vue.global.js	200	text/javascript	596715
62	38	script	fixture:/static/app.js	200	text/javascript	2443
64	0	other	fixture:/favicon.ico	—	—	0

Unknown sizes/phases are shown as unknown/—, never as zero.

Diagnostics — firefox

error · problem type: Functionality and interaction · signal source: javascript · pageerror

ReferenceError: undefinedHelper is not defined
    at init/< (http://[redacted]:57149/static/app.js:7:9)
    at EventListener.handleEvent*init (http://[redacted]:57149/static/app.js:6:11)
    at EventListener.handleEvent* (http://[redacted]:57149/static/app.js:48:14)
    at  (http://[redacted]:57149/static/app.js:52:3)

Location: fixture:/static/app.js:7:9 (generated/bundled position)

Observation phase: click-js-demo - Observed at: 1748 ms (navigation-relative). These describe when the diagnostic was observed, not its cause.

warning · problem type: Functionality and interaction · signal source: vue · console

[Vue warn]: Unhandled error during execution of native event handler 
  at <App>

Location: fixture:/static/vue.global.js:2446:15 (generated/bundled position)

Observation phase: click-vue-demo - Observed at: 2313 ms (navigation-relative). These describe when the diagnostic was observed, not its cause.

error · problem type: Functionality and interaction · signal source: vue · pageerror

TypeError: this.notDefinedOnPurpose is not a function
    at boom (http://[redacted]:57149/static/app.js:20:25)
    at callWithErrorHandling (http://[redacted]:57149/static/vue.global.js:2593:21)

Location: fixture:/static/app.js:20:25 (generated/bundled position)

Observation phase: click-vue-demo - Observed at: 2313 ms (navigation-relative). These describe when the diagnostic was observed, not its cause.

error · problem type: Resource loading · signal source: wasm · console

[demo wasm] instantiateStreaming failed: WebAssembly: Response has unsupported MIME type 'application/octet-stream' expected 'application/wasm'

Location: fixture:/static/app.js:39:19 (generated/bundled position)

Observation phase: click-wasm-demo - Observed at: 2885 ms (navigation-relative). These describe when the diagnostic was observed, not its cause.

Capability signals (evidence only, not a defect list): Vue detected=true (window.Vue global present; __vue_app__ marker on #vue-app; [Vue warn]: Unhandled error during execution of native event handler at <App>); Wasm supported=true, streaming=true, wasm resource seen=true; failures: streaming-mime: [demo wasm] instantiateStreaming failed: WebAssembly: Response has unsupported MIME type 'application/octet-stream' expected 'application/wasm'.

Performance — webkit

Sample	1 (authenticated context (actual sample cache mode; auto-login succeeded for this engine), local unthrottled, initial load)
TTFB	4 ms
DOMContentLoaded	55 ms
Load	56 ms
First Contentful Paint	57 ms
Largest Contentful Paint (observation-limited)	57 ms
Cumulative Layout Shift (observation-limited)	Not collected
Long tasks	Not collected
Long task total	Not collected
Observed entry types	largest-contentful-paint, event, first-input, mark, measure, navigation, paint, resource
Observation window	1506 ms

Resource waterfall — webkit (3 of initial-load window; later interaction resources excluded)

Start ms	Duration ms	Initiator	URL (redacted)	Status	MIME	Transfer B	Download ms
13	1	link	fixture:/static/style.css	—	—	514	0
14	4	script	fixture:/static/vue.global.js	—	—	596715	2
17	2	script	fixture:/static/app.js	—	—	2443	0

Unknown sizes/phases are shown as unknown/—, never as zero.

Diagnostics — webkit

error · problem type: Functionality and interaction · signal source: javascript · pageerror

ReferenceError: Can't find variable: undefinedHelper
    at unknown (http://[redacted]:57149/static/app.js:7:24)

Location: fixture:/static/app.js:7:24 (generated/bundled position)

Observation phase: click-js-demo - Observed at: 1695 ms (navigation-relative). These describe when the diagnostic was observed, not its cause.

warning · problem type: Functionality and interaction · signal source: vue · console

[Vue warn]: Unhandled error during execution of native event handler 
  at <App>

Location: fixture:/static/vue.global.js:2446:19 (generated/bundled position)

Observation phase: click-vue-demo - Observed at: 2316 ms (navigation-relative). These describe when the diagnostic was observed, not its cause.

error · problem type: Functionality and interaction · signal source: vue · pageerror

TypeError: this.notDefinedOnPurpose is not a function. (In 'this.notDefinedOnPurpose()', 'this.notDefinedOnPurpose' is undefined)
    at logError (http://[redacted]:57149/static/vue.global.js:2662:18)

Location: fixture:/static/vue.global.js:2662:18 (generated/bundled position)

Observation phase: click-vue-demo - Observed at: 2317 ms (navigation-relative). These describe when the diagnostic was observed, not its cause.

error · problem type: Resource loading · signal source: wasm · console

[demo wasm] instantiateStreaming failed: Unexpected response MIME type. Expected 'application/wasm'

Location: fixture:/static/app.js:39:24 (generated/bundled position)

Observation phase: click-wasm-demo - Observed at: 2945 ms (navigation-relative). These describe when the diagnostic was observed, not its cause.

Capability signals (evidence only, not a defect list): Vue detected=true (window.Vue global present; __vue_app__ marker on #vue-app; [Vue warn]: Unhandled error during execution of native event handler at <App>); Wasm supported=true, streaming=true, wasm resource seen=true; failures: streaming-mime: [demo wasm] instantiateStreaming failed: Unexpected response MIME type. Expected 'application/wasm'.

AI interpretation

AI interpretation: not available for this report (automated rule checks only — no AI attribution is claimed).

Limitations

This is a recorded local fixture run, replayed read-only — no new scan happens when the page opens.
Rule-based observation; no AI interpretation is attached to this public dataset.
Demo targets a fixed local fixture; external public URLs are never fetched in v0.1.
Findings shared across engines are not proven engine-specific.
Performance numbers come from a single initial-load sample on a fast local fixture; they are not customer-site or real-user metrics.
Source file/line/column are generated bundle positions; no public source map exists.
Evidence files (screenshots, logs) are omitted from the public dataset — none are requested or faked.

Evidence

No evidence artifacts were collected.

Live report (private, requires owner sign-in): /report/recorded-demo-20261013

Generated by BrowserSift prototype. Measurements are single-sample local observations, not production-user statistics.