$ git clone -n https://src.fedoraproject.org/rpms/R-highlight.git /var/lib/mock/f39-build-1470531-33902/root/chroot_tmpdir/scmroot/R-highlight
Cloning into '/var/lib/mock/f39-build-1470531-33902/root/chroot_tmpdir/scmroot/R-highlight'...
$ git fetch origin 3f5289e66c9616ded9a689defd3a88f3298e80a5:KOJI_FETCH_HEAD
From https://src.fedoraproject.org/rpms/R-highlight
 * [new ref]         3f5289e66c9616ded9a689defd3a88f3298e80a5 -> KOJI_FETCH_HEAD
$ git reset --hard KOJI_FETCH_HEAD
HEAD is now at 3f5289e Fix build requires