$ git clone -n https://src.fedoraproject.org/rpms/rust-errno.git /var/lib/mock/f39-build-2180282-51166/root/chroot_tmpdir/scmroot/rust-errno
Cloning into '/var/lib/mock/f39-build-2180282-51166/root/chroot_tmpdir/scmroot/rust-errno'...
$ git fetch origin a3345e2d7b0d6c8c61300df2aeef19244049dfba:KOJI_FETCH_HEAD
From https://src.fedoraproject.org/rpms/rust-errno
 * [new ref]         a3345e2d7b0d6c8c61300df2aeef19244049dfba -> KOJI_FETCH_HEAD
$ git reset --hard KOJI_FETCH_HEAD
HEAD is now at a3345e2 Update to version 0.3.8; Fixes RHBZ#2251840