Ask HN: Design principles for designing design tools like Figma, Photoshop etc.?

I've got a contract to design some interface concepts for a studio/editor type product. There are lots of products that fall into this category so I'm assuming someone must have written on the topic. Unfortunately, it's proving to be a difficult thing to google. Any recommendations? This is the only thing I've come across so far from Stas Aki at Readymag: https://readymag.com/readymag/design-principles/contents/