$ git clone -n https://src.fedoraproject.org/rpms/R-showtextdb.git /var/lib/mock/f45-build-6428-348/root/chroot_tmpdir/scmroot/R-showtextdb
Cloning into '/var/lib/mock/f45-build-6428-348/root/chroot_tmpdir/scmroot/R-showtextdb'...
$ git fetch origin 7ad3aac0ae0fcdcb46a3f3bb881598b626ca03b7:KOJI_FETCH_HEAD
From https://src.fedoraproject.org/rpms/R-showtextdb
 * [new ref]         7ad3aac0ae0fcdcb46a3f3bb881598b626ca03b7 -> KOJI_FETCH_HEAD
$ git reset --hard KOJI_FETCH_HEAD
HEAD is now at 7ad3aac Rebuilt for https://fedoraproject.org/wiki/Fedora_45_Mass_Rebuild