$ git clone -n https://src.fedoraproject.org/rpms/python-dulwich.git /var/lib/mock/f40-build-2222428-52703/root/chroot_tmpdir/scmroot/python-dulwich
Cloning into '/var/lib/mock/f40-build-2222428-52703/root/chroot_tmpdir/scmroot/python-dulwich'...
$ git fetch origin fe2a37937f77dcecf9f66dc9dc5ccc47ac07cb01:KOJI_FETCH_HEAD
From https://src.fedoraproject.org/rpms/python-dulwich
 * [new ref]         fe2a37937f77dcecf9f66dc9dc5ccc47ac07cb01 -> KOJI_FETCH_HEAD
$ git reset --hard KOJI_FETCH_HEAD
HEAD is now at fe2a379 Update to latest upstream release 0.21.7 (closes rhbz#2236973)