$ git clone -n https://src.fedoraproject.org/rpms/R-Rsamtools.git /var/lib/mock/f38-build-724370-99434/root/chroot_tmpdir/scmroot/R-Rsamtools
Cloning into '/var/lib/mock/f38-build-724370-99434/root/chroot_tmpdir/scmroot/R-Rsamtools'...
$ git fetch origin 2739e9d0fa29e6b0319af53c416ebff2885650bd:KOJI_FETCH_HEAD
From https://src.fedoraproject.org/rpms/R-Rsamtools
 * [new ref]         2739e9d0fa29e6b0319af53c416ebff2885650bd -> KOJI_FETCH_HEAD
$ git reset --hard KOJI_FETCH_HEAD
HEAD is now at 2739e9d R-maint-sig mass rebuild