$ git clone -n https://src.fedoraproject.org/rpms/rust-calloop.git /var/lib/mock/f39-build-2204455-51962/root/chroot_tmpdir/scmroot/rust-calloop
Cloning into '/var/lib/mock/f39-build-2204455-51962/root/chroot_tmpdir/scmroot/rust-calloop'...
$ git fetch origin 0759814bcf9b53a2d93cdee7707365dd28459fba:KOJI_FETCH_HEAD
From https://src.fedoraproject.org/rpms/rust-calloop
 * [new ref]         0759814bcf9b53a2d93cdee7707365dd28459fba -> KOJI_FETCH_HEAD
$ git reset --hard KOJI_FETCH_HEAD
HEAD is now at 0759814 Update to 0.12.3 (rhbz#2212365)