$ git clone -n https://src.fedoraproject.org/rpms/mate-user-guide.git /var/lib/mock/f45-build-18102-508/root/chroot_tmpdir/scmroot/mate-user-guide
Cloning into '/var/lib/mock/f45-build-18102-508/root/chroot_tmpdir/scmroot/mate-user-guide'...
$ git fetch origin be29b55ab49baea00489ef3a9c4cff45b6e00ca0:KOJI_FETCH_HEAD
From https://src.fedoraproject.org/rpms/mate-user-guide
 * [new ref]         be29b55ab49baea00489ef3a9c4cff45b6e00ca0 -> KOJI_FETCH_HEAD
$ git reset --hard KOJI_FETCH_HEAD
HEAD is now at be29b55 Rebuilt for https://fedoraproject.org/wiki/Fedora_45_Mass_Rebuild