$ git clone -n https://src.fedoraproject.org/rpms/R-pdftools.git /var/lib/mock/f39-build-1544596-36652/root/chroot_tmpdir/scmroot/R-pdftools
Cloning into '/var/lib/mock/f39-build-1544596-36652/root/chroot_tmpdir/scmroot/R-pdftools'...
$ git fetch origin 21b15855089d5e37ef5d4b10fdad98fb29939a32:KOJI_FETCH_HEAD
From https://src.fedoraproject.org/rpms/R-pdftools
 * [new ref]         21b15855089d5e37ef5d4b10fdad98fb29939a32 -> KOJI_FETCH_HEAD
$ git reset --hard KOJI_FETCH_HEAD
HEAD is now at 21b1585 Rebuilt for https://fedoraproject.org/wiki/Fedora_39_Mass_Rebuild