refs (`FrozenSet[str]`):
Set of `refs` pointing to this revision. If the revision has no `refs`, it
is considered detached.
Example: `{"main", "2.4.0"}` or `{"refs/pr/1"}`.
size_on_disk (`int`):
Sum of the blob file sizes that are symlink-ed by the revision.
last_modified (`float`):
Timestamp of the last time the revision has been created/modified.