$ git clone -n https://src.fedoraproject.org/rpms/libtevent.git /var/lib/mock/f40-build-2008519-45381/root/chroot_tmpdir/scmroot/libtevent
Cloning into '/var/lib/mock/f40-build-2008519-45381/root/chroot_tmpdir/scmroot/libtevent'...
$ git fetch origin 6b8420a54cb2cfd9c323ec074359820db0429092:KOJI_FETCH_HEAD
From https://src.fedoraproject.org/rpms/libtevent
 * [new ref]         6b8420a54cb2cfd9c323ec074359820db0429092 -> KOJI_FETCH_HEAD
$ git reset --hard KOJI_FETCH_HEAD
HEAD is now at 6b8420a Update to version 0.16.0