Twitter's main Explore page emphasizes sports, entertainment, animals...and now Biden tweets.
Which is interesting, since Musk is no fan, and since there've been times in the past when he was apparently shadowbanning Biden, who wouldn't show up under Trending topics even when he was getting a lot of positive media attention. I don't know if Biden is showing up under Trending now, since Twitter has made changes in the last week so people who aren't logged in can't view Trending, or use search. I can see tweets only by looking at the main Explore page, or using a bookmark or Google link to go straight to an individual account.
There's no way Musk is trying to help Biden by making his tweets more visible.
I think Musk wants anyone who might click on those tweets to see all the thousands of deranged, vicious RWNJ replies to Biden, which are 90+% of the replies you'll see now that replies posted by Twitter subscribers are ALL given priority over all of the replies from non-subscribers, who are much more likely to be liberals and Biden supporters.
Musk wants it to appear to the world that Biden is hated and despised, so he's giving Biden's tweets much more exposure on the Explore page than I ever noticed before. Anyone clicking on one of Biden's tweets now will see replies like the ones here:
Probably makes psychopath Musk giggle every time he sees this sort of thing.