I can think of worse ideas but is there enough "meat" there for a project? (bear in mind this project has mostly come from dev tool element inspection rather than digging through the source code so I don't have a good grasp of the extent of this.

Eventually I'd like to get to a point with this where this could start to be reduced to the point where one could define an actual design system/pattern library/design languague (whatever the actual technically correct term is) with modular and reusable elements (i.e. modal dialogs have x font, y buttons in z layout) which would have the benefit of making life easier (and more consistent) for all kinds of things - new ui features, plugins, "third party" apps & tools, theming support etc.