$ git clone -n https://src.fedoraproject.org/rpms/llvm8.0.git /var/lib/mock/f39-build-1854058-42382/root/chroot_tmpdir/scmroot/llvm8.0
Cloning into '/var/lib/mock/f39-build-1854058-42382/root/chroot_tmpdir/scmroot/llvm8.0'...
$ git fetch origin 66ee8e0b0d7315880127b800ea564507db49fd20:KOJI_FETCH_HEAD
From https://src.fedoraproject.org/rpms/llvm8.0
 * [new ref]         66ee8e0b0d7315880127b800ea564507db49fd20 -> KOJI_FETCH_HEAD
$ git reset --hard KOJI_FETCH_HEAD
HEAD is now at 66ee8e0 Rebuilt for https://fedoraproject.org/wiki/Fedora_39_Mass_Rebuild