I don’t have screenshots to visualize it, but I’ve attempted to explain how to do it in the webstore here:
Finishing a how-to with screenshots will help a lot more people and will probably be more easy to understand and follow, so please finish your guide for that, impeccably-stressed!
There’s also a way to extract the app.asar file of the more modern CoG/HG games bought on Steam (there’s a different, easier method for older games like Tin Star), but it needs a bit of set up and I’d need to find the original post where that was explained to attempt to describe it in more simple words. As not every game is released on Steam in the first place though, the webstore is the way easier method, especially if you can buy in the webstore directly and don’t have to go the purchase transfer route first.
