googlemaps, what are the grey areas? Does anyone have a key?

[QueryA]

Why are some areas grey on google maps? Its not towns, the areas seem to be remote. Its not country parks or national parks. I always thought the beige was mountians, but looking at it I don't think that can be correct either. I can't find a map key to figure it out. Anyone know?

https://www.boondockersbible.com/learn/what-do-the-different-colors-mean-on-google-maps/

Apparently grey is volcanic rock/tundra but satellite imagery might be a bit confusing for the algorithm.

Thanks, that’s really helpful having a key. I think the algorithm must be a bit patchy as some of the highlighted areas are unlikely tundra/rock. But at least it’s not urban which is what was really confusing me 😆