FWIW this is also true on the design side. I've researched a lot of design teams and their custom tooling (I worked on design tools at Atlassian and now am working on them at Figma). Facebooks is leagues above the rest. I've been blown away at what they do there. Some really amazing engineering and design thinking happening on Facebook's internal tooling.
I'd love to know concretely what this means. I don't feel like I see 100s of design related stuff coming out of FB so it's hard to imagine they even need design tools. Maybe I'm just not aware of all of FBs products and world class design.
It's a prototyping tool, I don't believe it has any codegen facilities. It used to be a Quartz Composer framework and then it evolved in to a standalone app.
