I would like to know what they mean by that. Like a Spinoza-Einstein higher power, or a diest higher power, or go to services once a year higher power…

Belief in a higher power is pretty vague. If you pushed me I might concede that since I believe that our universe has operating laws and humans have the ability to understand them I believe in a higher power that is our understanding of these laws. That the community that is humanity can produce a collective understanding that is greater than we can produce as individuals. In this very vague sense I believe in a higher power. I would prefer we just call it our collective knowledge but whatever.