$ git clone -n https://src.fedoraproject.org/rpms/flatpak.git /var/lib/mock/f39-build-1578467-37997/root/chroot_tmpdir/scmroot/flatpak
Cloning into '/var/lib/mock/f39-build-1578467-37997/root/chroot_tmpdir/scmroot/flatpak'...
$ git fetch origin 2e0f03b2a71f8dfc4ac5942ee4a1e0f6f7cb2212:KOJI_FETCH_HEAD
From https://src.fedoraproject.org/rpms/flatpak
 * [new ref]         2e0f03b2a71f8dfc4ac5942ee4a1e0f6f7cb2212 -> KOJI_FETCH_HEAD
$ git reset --hard KOJI_FETCH_HEAD
HEAD is now at 2e0f03b Switch libs deps to ostree-libs