1754431 - "Watch later" option is not available on embedded YouTube video on about.google with ETP - Standard enabled

Status: RESOLVED WONTFIX

(Core :: Privacy: Anti-Tracking, defect, P3)

Description

[Oana Arbuzov [:oanaarbuzov]]

Attachment: standardVsDisabled.png

Environment:
Browser / Version: Firefox Nightly 99.0a1 (2022-02-08), Firefox Nightly 99.0a1 (🦎 99.0a1-20220208070047)
Operating System: Windows 10 Pro, Google Pixel 5 (Android 12) - 1080 x 2340 pixels, 19.5:9 ratio (~432 ppi density), Samsung Galaxy S8 (Android 9) - 1440 x 2960 pixels, 18.5:9 ratio (~570 ppi density)

Prerequisites:
ETP - Standard enabled.
Signed into Google account.

Steps to Reproduce:

1. Navigate to https://about.google/products/#!/recommended
2. Scroll down the page until reaching the embedded YouTube video.
3. Click to play the video.
4. Observe available options on top right side of the video.

Expected Behavior:
"Watch later" option is available.

Actual Behavior:
"Watch later" option is not available.

Notes:

1. Screenshot attached.
2. The issue is not reproducible with ETP disabled.
3. Also reproducible on mobile.

Comment 1

[Benjamin VanderSloot [:bvandersloot]]

This occurs because youtube.com doesn't have access to cookies on about.google.

Typically the watch later button sends a request to youtube.com/edit_playlist?key=USERS_UNIQUE_WATCH_LATER_ID. This can't work without access to YouTube's cookies (the precise mechanism is unclear). We block youtube's cookie access as a third party because of its inclusion in the Disconnect Content List.

This can be mitigated if the YouTube iframe requests Storage Access.

However, I don't think we should intervene and shim for an entity with cookies blocked by the Disconnect list.

Comment 2

[Benjamin VanderSloot [:bvandersloot]]

Raised with YouTube in the best way I could find: https://stackoverflow.com/questions/71221413/youtube-embedded-iframes-dont-show-watch-later-on-firefox-without-third-party-c .

As discussed in our breakage meeting, this is a WONTFIX as it is not sufficiently broken to merit shimming a member of the Disconnect list.