$ git clone -n https://src.fedoraproject.org/rpms/R-microbenchmark.git /var/lib/mock/f42-build-side-1-3501702-45976/root/chroot_tmpdir/scmroot/R-microbenchmark
Cloning into '/var/lib/mock/f42-build-side-1-3501702-45976/root/chroot_tmpdir/scmroot/R-microbenchmark'...
$ git fetch origin 39b65228a03000c28ee59f4fe5f00cf20b8bc74e:KOJI_FETCH_HEAD
From https://src.fedoraproject.org/rpms/R-microbenchmark
 * [new ref]         39b65228a03000c28ee59f4fe5f00cf20b8bc74e -> KOJI_FETCH_HEAD
$ git reset --hard KOJI_FETCH_HEAD
HEAD is now at 39b6522 R-maint-sig mass rebuild