$ git clone -n https://src.fedoraproject.org/rpms/rubygem-between_meals.git /var/lib/mock/f45-build-34795-691/root/chroot_tmpdir/scmroot/rubygem-between_meals
Cloning into '/var/lib/mock/f45-build-34795-691/root/chroot_tmpdir/scmroot/rubygem-between_meals'...
$ git fetch origin 3a130e21b21fc90b3ca6129a88d89dcc8d9afa86:KOJI_FETCH_HEAD
From https://src.fedoraproject.org/rpms/rubygem-between_meals
 * [new ref]         3a130e21b21fc90b3ca6129a88d89dcc8d9afa86 -> KOJI_FETCH_HEAD
$ git reset --hard KOJI_FETCH_HEAD
HEAD is now at 3a130e2 Rebuilt for https://fedoraproject.org/wiki/Fedora_45_Mass_Rebuild