Those are the files (including the STL) of ergonomic keycaps : DES keycaps.
Here is the github repository of the creator : https://github.com/pseudoku/PseudoMakeMeKeyCapProfiles
I chose to export them with the stem parameter ("Tol" variable in the openscad file) value of 0.055 as it fitted best my MX switches when I 3d printed them on my resin printer, but you can easily make those files yourself by following the “readme.md” in the github repository above, so that you will chose which values fits you best.
Also I didn't export all variations of those keycaps (no convex one for example), so you would need to generate them yourself if you want them.
The author remixed this model.
I made the STL files available here as I know the process of generating them on openscad (installing library …) can discourage a lot who would have printed them if they had the STL.
I also made some modifications on the homerow keycap by adding a bump for the index finger version.