https://www.gnu.org/software/make/manual/html_node/Catalogue...
There are two things to note: (1) you can turn them off so they don't get in the way of other use cases, (2) they include non-build stuff like version control, linting, and document generation.
There's also a whole chapter on ar file maintenance. This is mostly useful for linking these days, but ar is the precursor to tar, so this used to also be useful for running filesystem backups:
https://www.gnu.org/software/make/manual/html_node/Archives....