From Linx on Discord:

A quick look at the detail heightmaps in action and how fast it is to make edits to the terrain. It’s pretty satisfying to see the textures update to reflect the new context of the terrain. I spent longer than I should have playing around with this!

Detail heightmaps are per-biome so planets won’t have the same one everywhere. Due to their tiling/repeating nature they won’t be used in places where that becomes obvious; I’m thinking they’ll be applied to slopes or cliffs to add some extra detail to stop them from looking lumpy. I’m also going to be looking into procedural elements! Procedural noise is great for adding non-repeating detail that also isn’t limited by the resolution of a texture, but requires a lot of care so that different locations don’t look “samey”. The planets will still be mostly driven by heightmaps, but closer to the surface where the heightmap resolution becomes too low is where procedural elements shine - KSP uses this. Not sure how far down that rabbit hole we’ll go as I’ve only recently started looking into it, but it’s something I’m interested in.

I leave you with a fun fact: Minmus in KSP is entirely procedural. If you change the seed using a mod you get an entirely new version of the minty moon 😉