Lemmy support would be much more fitting for Mozilla. They could add plugin or lemmy integration to their browser that could show discussions from subscribed communities matching the current url.
Effectively acting as a "comment section" but for any page. One would only need lemmy account to comment on youtube videos, news articles, blogs etc.
Well since they were/are hosting Mastodon instance they do seem to have some interest in the fediverse. They do also have official plugins.
Personally I feel something like this could be the next step for social link aggregation and discussion platforms. Being able to share and discuss on about videos and articles without having to register to dozens or more pages while also having some control over the people you interract with through instances, subscribed communities etc.
Source media would also be unable to control what can or cannot be discussed. Many youtube videos and news articles for example may block all comments. It would be up to community on how to moderate discussion.