Have some measure of redundancy for crates in the community index.

Check Software Heritage:

• You can request for any repository to be mirrored
• We can request this via API during index checks, or move the request to the client side
  • Probably better allow the users to opt-out of it, so we could have an option in origins and a setting
• Once mirrored (pretty fast), a commit can be requested as a tar.gz file via API
  • We could use this with a fallback deployer
  • We could have a global setting to work directly from the heritage site
  • Generating the tarball for the first time is pretty slow

Check what OPAM did about it:

• They use a swhid as a mirror for an origin

We can batch-add existing crates from core maintainers (myself, fabien, others?) at a later time.