$ git clone -n https://src.fedoraproject.org/rpms/libblockdev.git /var/lib/mock/f39-build-2265520-54601/root/chroot_tmpdir/scmroot/libblockdev
Cloning into '/var/lib/mock/f39-build-2265520-54601/root/chroot_tmpdir/scmroot/libblockdev'...
$ git fetch origin 5d95864c49f2c5f8fa760c264fc0b01a28740e9f:KOJI_FETCH_HEAD
From https://src.fedoraproject.org/rpms/libblockdev
 * [new ref]         5d95864c49f2c5f8fa760c264fc0b01a28740e9f -> KOJI_FETCH_HEAD
$ git reset --hard KOJI_FETCH_HEAD
HEAD is now at 5d95864 New version 3.1.0