$ git clone -n https://src.fedoraproject.org/rpms/rust-errno.git /var/lib/mock/f39-build-1517137-35689/root/chroot_tmpdir/scmroot/rust-errno
Cloning into '/var/lib/mock/f39-build-1517137-35689/root/chroot_tmpdir/scmroot/rust-errno'...
$ git fetch origin 6c5c83130ebad2ba53c49d8d433002504db1b894:KOJI_FETCH_HEAD
From https://src.fedoraproject.org/rpms/rust-errno
 * [new ref]         6c5c83130ebad2ba53c49d8d433002504db1b894 -> KOJI_FETCH_HEAD
$ git reset --hard KOJI_FETCH_HEAD
HEAD is now at 6c5c831 Update to version 0.3.4; Fixes RHBZ#2241645