I wanted to build something like this but for Linux, especially the vimium-like hints that would work in any app. I even made a prototype by abusing the AT-SPI2 accessibility API. Unfortunately, querying AT-SPI2 for all buttons takes too long in complex apps. And even if it was fast, many apps (especially non-GTK ones) implement accessibility poorly or don't implement it at all, so I abandoned the project.
I guess it would be possible to make a framework specific implementation, for example by replacing the GTK shared library with a modified version, but that's too much effort and I lost interest in the whole 'mouseless' thing anyway.
I guess it would be possible to make a framework specific implementation, for example by replacing the GTK shared library with a modified version, but that's too much effort and I lost interest in the whole 'mouseless' thing anyway.