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YouTube and Twitch Video Helpers

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YouTube and Twitch use small, site-specific content helpers on top of normal DNR blocking. Cosmetic hiding targets dedicated ad-only elements; the player region and real content are never touched. See Cosmetic Filtering for the full policy.

YouTube

Video ads are removed at the source. A MAIN-world script (content/yt-inpage.ts) runs in the page's own context at document_start and deletes the ad instructions (adPlacements, adSlots, playerAds) from YouTube's Innertube JSON wherever it enters the app:

  • The inline ytInitialPlayerResponse (first video) and ytInitialData (first browse/search render), via accessors installed before either is assigned.
  • Responses fetched over fetch or XMLHttpRequest for the ad-carrying endpoints (/youtubei/v1/{player,get_watch,browse,search,playlist,reel_watch_sequence}, plus the legacy playlist?list= HTML endpoint). XHR matters because YouTube's TV/mobile web clients still use it, and a response read there never touches the fetch wrap.
  • Fresh realms: a page that runs after us can grab pristine fetch/JSON.parse from a dynamically inserted iframe and bypass every hook, so dynamically added same-origin frames are patched the moment they become reachable.

With no ads to schedule, the player starts the real video immediately; streamingData and everything else is left intact. This is uBlock Origin's approach and is much cleaner than fast-forwarding. It honors the off switch, allowlist, and YouTube toggle via a config message from the isolated content script, and reports removed ads back for stats. The same pruning runs on youtube-nocookie.com, the privacy-enhanced embed host.

On top of that source-level pruning, the isolated content script:

  • Detects youtube.com (and youtube-nocookie.com) hostnames.
  • Hides feed, masthead, display, and companion ad elements (ytd-ad-slot-renderer, ytd-display-ad-renderer, #masthead-ad, and the grid cells that wrap them) without hiding real videos, comments, Shorts, or recommendations.
  • Clicks visible ad skip buttons and fast-forwards any ad-showing / ad-interrupting pre/mid-roll — a safety net for ads that slip past the pruner — then resumes playback when the ad period ends, so the video starts on its own instead of staying paused.
  • Dismisses the "ad blockers violate Terms" enforcement popup — hides the modal and shared backdrop, restores scrolling, and resumes playback, only when the enforcement message is present.
  • Records estimated video seconds saved when an ad is pruned, skipped, or fast-forwarded — one credit per ad period even though both the skip click and the fast-forward fire for it.

These behaviors are tested with cached YouTube-like pages served as www.youtube.com in Bun WebView, asserting ads are hidden and skipped while the real feed video, comments, <video>, and skip button stay visible and playback continues. test/youtube-prune.test.ts runs the built yt-inpage.js in real Chromium and asserts ads are stripped from inline and fetched player responses while streamingData survives, and test/youtube-defense.test.ts additionally covers XHR-delivered responses, ytInitialData assignment, the iframe-realm bypass, and playback auto-resume after an ad ends.

Twitch

The content script:

  • Detects twitch.tv hostnames.
  • Hides Twitch's ad-only affordances — the "Leave feedback for this Ad" / "Learn more about this ad" buttons and the anti-adblock nag overlay. (Twitch now stitches video ads into the stream server-side, so the old display-banner containers no longer exist and were dropped.)
  • Records estimated video seconds saved when Twitch video-ad markers appear — the markers stay visible because the ad is the live stream itself.
  • Uses throttled mutation scans so stream chat and live page updates stay responsive.

Twitch changes often, so the implementation focuses on ad-affordance hiding plus marker detection instead of brittle player rewrites.

Limits

These sites change often. The implementation favors precise, ad-only selectors, visible skip-button automation, and passive marker detection over fragile playback hacks or broad DOM hiding that risk breaking normal use.