A process/methodology pattern that describes a general approach, not specific techniques. Specific techniques might be suggested, but they're not necessarily the best ones or the only ones. As an example, EliminateDesignDebt recommends eliminating DesignDebt, and suggests DoTheSimplestThingThatCouldPossiblyWork as a possible technique.
What's the difference between a ProcessPrinciple and a ProcessPattern? Perhaps that a ProcessPrinciple suggests multiple ProcessPatterns / techniques. Different ones would be applicable for different projects. If you can't think of multiple techniques that are good for your ProcessPrinciple, maybe it's actually a ProcessPattern instead.