Since I'm working on extensions and not so much core (but still want to be able to get to core info), your configuration for it isn't going to work for me. And while .dir-locals.el files have their uses, it looks like you have to use hack-local-variables.
I've started using a particular layout for MediaWiki + extensions, configuration, and skins, that makes this a little more difficult. I don't have extensions deployed in mediawiki/extensions, but in another place with symlinks and such to make web servers happy.
This means I can manage git repositories a little bit more sanely (for me, anyway) but it also means that Serenata isn't necessarily going to see the MediaWiki unless I point right to it.
Oh, and I'm dealing with multiple versions of MW for different clients, so I can't point to just one MW install.
Put this all together and I have to have a way to tell Emacs, lsp-mode, and Serenata how to find the parent MediaWiki for a given project. And, I think I want Serenata to use one sqlite db per project. Which will mean that $CLIENT1's MW+extensions, etc will all be stored in SQLITE-DIR1, while $CLIENT2's stuff will be in SQLITE-DIR2.
BTW, this is all made more difficult because MW wants to be its own special snowflake and avoid the common autoloader logic that PHP is migrating to.