mostly doing this to add the comment so someone else doesn't try to package libturbojpeg again

... so I assume you want to remove pkgs/development/libraries/libturbojpeg/default.nix from the PR?

And perhaps you want to add yourself into meta.maintainers? I can't say I really maintain the package, but it certainly feels important enough to me.

Hm. I'm really only sending this PR because (1) I started it thinking libturbojpeg wasn't packaged (and want to add the comment for anyone else grepping), and (2) someone in IRC encouraged me to go ahead and update this one since it's a bugfix behind.

I don't use it directly, or know anything about it. I don't mind sending updates for it, or adding it to my list of packages to keep an eye on, but other than that, I'm not qualified to "maintain" this if it ever required any non-trivial maintenance work.

What would be the guidance for me? I'm finding myself wondering, "What exactly is the implication of putting my name in that array?".

There's not much implication; it's still not defined anywhere AFAIK :-) Mainly you get mentioned here when someone wants something about the package. I think @GrahamcOfBorg now automatically requests reviews from meta.maintainers when it detects changes in the corresponding file. And maintainers are generally expected to react to these in some way.

EDIT: actually you can see the bot in action just above this comment :-)