$ git clone -n https://src.fedoraproject.org/rpms/R-waveslim.git /var/lib/mock/f38-build-723916-99307/root/chroot_tmpdir/scmroot/R-waveslim
Cloning into '/var/lib/mock/f38-build-723916-99307/root/chroot_tmpdir/scmroot/R-waveslim'...
$ git fetch origin 8355fb92c82a75d8ba52e504ff653ebd5c9edd27:KOJI_FETCH_HEAD
From https://src.fedoraproject.org/rpms/R-waveslim
 * [new ref]         8355fb92c82a75d8ba52e504ff653ebd5c9edd27 -> KOJI_FETCH_HEAD
$ git reset --hard KOJI_FETCH_HEAD
HEAD is now at 8355fb9 R-maint-sig mass rebuild