$ git clone -n https://src.fedoraproject.org/rpms/R-callr.git /var/lib/mock/f40-build-2031938-47655/root/chroot_tmpdir/scmroot/R-callr
Cloning into '/var/lib/mock/f40-build-2031938-47655/root/chroot_tmpdir/scmroot/R-callr'...
$ git fetch origin 8cb8045c93bfda6754b8172a689ca2b55e6601d8:KOJI_FETCH_HEAD
From https://src.fedoraproject.org/rpms/R-callr
 * [new ref]         8cb8045c93bfda6754b8172a689ca2b55e6601d8 -> KOJI_FETCH_HEAD
$ git reset --hard KOJI_FETCH_HEAD
HEAD is now at 8cb8045 Rebuilt for https://fedoraproject.org/wiki/Fedora_39_Mass_Rebuild