$ git clone -n https://src.fedoraproject.org/rpms/R-cachem.git /var/lib/mock/f45-build-5995-345/root/chroot_tmpdir/scmroot/R-cachem
Cloning into '/var/lib/mock/f45-build-5995-345/root/chroot_tmpdir/scmroot/R-cachem'...
$ git fetch origin 0bcfa9633ca803120416168f9df2487d504c2141:KOJI_FETCH_HEAD
From https://src.fedoraproject.org/rpms/R-cachem
 * [new ref]         0bcfa9633ca803120416168f9df2487d504c2141 -> KOJI_FETCH_HEAD
$ git reset --hard KOJI_FETCH_HEAD
HEAD is now at 0bcfa96 Rebuilt for https://fedoraproject.org/wiki/Fedora_45_Mass_Rebuild