Clean up / document VCS used in weblate installation

While looking for the VCS used on the translation server, I see under
/var/lib/weblate/repositories/vcs
3 different folders.
Can you please either clean this up or document what each folder does?
Thanks!

Parent Task: #11759 (closed)

Original created by @u on 15479 (Redmine)

To upload designs, you'll need to enable LFS and have an admin enable hashed storage. More information