coreos/docs — pull request #328 by anonymuse (2014-09-16 19:41:46+00:00)
Title: X-Fleet variable requires 'X-' prefix.

- The older 'ConditionMachineOf' nomenclature requires 'X-'
- Can also be updated to 'MachineOf' from v.0.8.0, but that
doesn't match the rest of the documentation.