$ git clone -n https://src.fedoraproject.org/rpms/edk2.git /var/lib/mock/f39-build-2029698-47476/root/chroot_tmpdir/scmroot/edk2
Cloning into '/var/lib/mock/f39-build-2029698-47476/root/chroot_tmpdir/scmroot/edk2'...
$ git fetch origin b1b2afe95778f5fe01e281d48b70ceadb14f8307:KOJI_FETCH_HEAD
From https://src.fedoraproject.org/rpms/edk2
 * [new ref]         b1b2afe95778f5fe01e281d48b70ceadb14f8307 -> KOJI_FETCH_HEAD
$ git reset --hard KOJI_FETCH_HEAD
HEAD is now at b1b2afe switch the strictnx build to qcow2 (like all other 4M builds)