Or does a self hosted lemmy instance federate all comments from all threads once it knows about a server?
Only in subscribed communities, but yes.
If it’s been opened and had anything replaced, unless they’re better than 99% of the DIY steam deck crowd, they left small traces of getting past the backplate.
For what it’s worth, I believe the general consensus is that Valve cannot reject your warranty claim for the device having been opened under US law (the FTC has gone after other manufacturers for this).
On the other hand, I don’t really trust Reddit with my upvotes/downvotes all that much more than random users, so I already refrain from voting on content I wouldn’t want to be associated with…
Of course, Reddit can still see what posts I view, while that isn’t the case for Lemmy (at least since I self-host an instance).
The PR hadn’t been reviewed and was merged by mistake, from my understanding.