$ git clone -n https://src.fedoraproject.org/rpms/mbedtls.git /var/lib/mock/f39-build-1470767-33919/root/chroot_tmpdir/scmroot/mbedtls
Cloning into '/var/lib/mock/f39-build-1470767-33919/root/chroot_tmpdir/scmroot/mbedtls'...
$ git fetch origin 5e8fef2390f2fdd684d3ee36ef89e062a791ce3d:KOJI_FETCH_HEAD
From https://src.fedoraproject.org/rpms/mbedtls
 * [new ref]         5e8fef2390f2fdd684d3ee36ef89e062a791ce3d -> KOJI_FETCH_HEAD
$ git reset --hard KOJI_FETCH_HEAD
HEAD is now at 5e8fef2 Update to 2.28.5