> So I could just replace packages/auctex with some other clone of
> auctex.git?
Yes.
>> So your first and third steps above can happen at some other time.
> Alright. But I currently don't understand how "make packages/auctex"
> knows which commit to check out.
The first `make packages/auctex` just does
git worktree add packages/auctex externals/auctex
you can `git clone .../auctex.git` there instead.
> And nowhere in the elpa repository do I find some statement that for
> auctex the externals/auctex branch in elpa.git is to be used instead
> of the main or master branch of auctex.git.
It's always built from `externals/<PKG>`.
The sync between those branches and an upstream (according to `:url`) is
performed separately by another cron job (it could run on another
machine, tho it currently doesn't).
> [1] It just occurred to me that in all mails I've written about an
> externals/elpa branch which is actually externals/auctex.
🙂
Stefan