$ git clone -n https://src.fedoraproject.org/rpms/R-jpeg.git /var/lib/mock/f45-build-6220-347/root/chroot_tmpdir/scmroot/R-jpeg
Cloning into '/var/lib/mock/f45-build-6220-347/root/chroot_tmpdir/scmroot/R-jpeg'...
$ git fetch origin b35079df981e69394142fb76fce3bc1a4dba9b78:KOJI_FETCH_HEAD
From https://src.fedoraproject.org/rpms/R-jpeg
 * [new ref]         b35079df981e69394142fb76fce3bc1a4dba9b78 -> KOJI_FETCH_HEAD
$ git reset --hard KOJI_FETCH_HEAD
HEAD is now at b35079d Rebuilt for https://fedoraproject.org/wiki/Fedora_45_Mass_Rebuild