Deleting a branch from a shared repository. Is ti possible? Does it matter?

[Matiyam]

Hi!

I have a shared repository and some experimental branches inside it.

Is it possible to delete some of the branches?

Does it matter? I mean, maybe the storage they take is negible and it's not
worth it.

By the way, if i have a repo with --no-trees option initialised, is there a way
to know which branches it contains?

Thanks a lot for this wonderful software!!

-- M