$ git clone -n https://src.fedoraproject.org/rpms/ghc-mmap.git /var/lib/mock/f40-build-1998124-44210/root/chroot_tmpdir/scmroot/ghc-mmap
Cloning into '/var/lib/mock/f40-build-1998124-44210/root/chroot_tmpdir/scmroot/ghc-mmap'...
$ git fetch origin 097699d4df718241a6d4aafa39be86185aeeacdc:KOJI_FETCH_HEAD
From https://src.fedoraproject.org/rpms/ghc-mmap
 * [new ref]         097699d4df718241a6d4aafa39be86185aeeacdc -> KOJI_FETCH_HEAD
$ git reset --hard KOJI_FETCH_HEAD
HEAD is now at 097699d bump release