$ git clone -n https://src.fedoraproject.org/rpms/libX11.git /var/lib/mock/f45-build-15778-479/root/chroot_tmpdir/scmroot/libX11
Cloning into '/var/lib/mock/f45-build-15778-479/root/chroot_tmpdir/scmroot/libX11'...
$ git fetch origin b6a63dd4b16621e52a78422c5c4691e3a328f55e:KOJI_FETCH_HEAD
From https://src.fedoraproject.org/rpms/libX11
 * [new ref]         b6a63dd4b16621e52a78422c5c4691e3a328f55e -> KOJI_FETCH_HEAD
$ git reset --hard KOJI_FETCH_HEAD
HEAD is now at b6a63dd Rebuilt for https://fedoraproject.org/wiki/Fedora_45_Mass_Rebuild