Unrortunatelly a randomly generated id, used to count your likes and dislikes (without any link to your email or YouTube account) is still "personally identifying data".

and my standard copy-pasta full explainer:

The extension is actually recommended by Mozilla, so they do not consider it harmful or dangerous.

RYD hasn’t changed how it handles your data. What changed is how Mozilla labels these permissions - not what the extension does with your data.

Ajay, the author of SponsorBlock and DeArrow, has also raised this issue with Mozilla. He explains how the new wording can make an existing extension look like it suddenly started collecting new data, without making clear which websites it can access. You can read his post on Mozilla’s forum here: https://discourse.mozilla.org/t/the-new-data-transmission-permissions-seem-to-be-misleading-to-users/149410

The extension only uses the data it needs to show dislikes and count votes.

Its site permissions cover YouTube and its own API at returnyoutubedislikeapi.com. RYD doesn’t read other websites, and these site permissions cannot be used to access them.

Here’s what those permissions mean.

Personally identifiable information - RYD’s randomly generated, anonymous user ID, used to count votes. This isn’t your Google or YouTube account.

Browsing activity - opening the next YouTube video, so the extension can send its video ID and fetch the new dislike count.

Website content - things like the visible like count, which helps calculate dislike estimates.

Website activity - clicking Like or Dislike.

Again, this is about YouTube activity. The extension isn’t watching everything you do across the internet - it simply can’t do that with these site permissions.

The new labels sound scary, but they don’t give the extension access to more websites.

RYD is open source, so you can see how it works here: https://github.com/Anarios/return-youtube-dislike