$ git clone -n https://src.fedoraproject.org/rpms/rubygem-minitest.git /var/lib/mock/f39-build-1499368-34744/root/chroot_tmpdir/scmroot/rubygem-minitest
Cloning into '/var/lib/mock/f39-build-1499368-34744/root/chroot_tmpdir/scmroot/rubygem-minitest'...
$ git fetch origin ed177e079667238603cbc2cf8f55d86e5b62b103:KOJI_FETCH_HEAD
From https://src.fedoraproject.org/rpms/rubygem-minitest
 * [new ref]         ed177e079667238603cbc2cf8f55d86e5b62b103 -> KOJI_FETCH_HEAD
$ git reset --hard KOJI_FETCH_HEAD
HEAD is now at ed177e0 5.20.0