$ git clone -n https://src.fedoraproject.org/rpms/yggdrasil.git /var/lib/mock/f45-build-39270-733/root/chroot_tmpdir/scmroot/yggdrasil
Cloning into '/var/lib/mock/f45-build-39270-733/root/chroot_tmpdir/scmroot/yggdrasil'...
$ git fetch origin 57c24d5f2015d513b7a85f3c6ae02b4e2a82ed97:KOJI_FETCH_HEAD
From https://src.fedoraproject.org/rpms/yggdrasil
 * [new ref]         57c24d5f2015d513b7a85f3c6ae02b4e2a82ed97 -> KOJI_FETCH_HEAD
$ git reset --hard KOJI_FETCH_HEAD
HEAD is now at 57c24d5 Rebuilt for https://fedoraproject.org/wiki/Fedora_45_Mass_Rebuild