$ git clone -n https://src.fedoraproject.org/rpms/R-lmtest.git /var/lib/mock/f38-build-724008-99307/root/chroot_tmpdir/scmroot/R-lmtest
Cloning into '/var/lib/mock/f38-build-724008-99307/root/chroot_tmpdir/scmroot/R-lmtest'...
$ git fetch origin 4a084d34d504e75aea88de7a54f2d7a85cc5f8c6:KOJI_FETCH_HEAD
From https://src.fedoraproject.org/rpms/R-lmtest
 * [new ref]         4a084d34d504e75aea88de7a54f2d7a85cc5f8c6 -> KOJI_FETCH_HEAD
$ git reset --hard KOJI_FETCH_HEAD
HEAD is now at 4a084d3 R-maint-sig mass rebuild