$ git clone -n https://src.fedoraproject.org/rpms/docker-buildx.git /var/lib/mock/f45-build-7769-369/root/chroot_tmpdir/scmroot/docker-buildx
Cloning into '/var/lib/mock/f45-build-7769-369/root/chroot_tmpdir/scmroot/docker-buildx'...
$ git fetch origin 4c6f7c15908eda215c42feb52fbdc64dc09af3e3:KOJI_FETCH_HEAD
From https://src.fedoraproject.org/rpms/docker-buildx
 * [new ref]         4c6f7c15908eda215c42feb52fbdc64dc09af3e3 -> KOJI_FETCH_HEAD
$ git reset --hard KOJI_FETCH_HEAD
HEAD is now at 4c6f7c1 Update to release v0.37.0