MacOS Mojave disable all 4 rounded window corners either with defaults, or software, or programatically


Is there a system API, or utility (open source), or default I can set to disable all 4 rounded window corners on macOS?

I've checked the two other prominent questions relating to this:

  1. Can I change 10.8.2 Mountain Lion window corners from rounded to squared?
  2. How can I disable rounded window corners in OS X

And the links are either dead, or the offered solution does not work.

Best Answer

I figured it out, I used ThemeEngine to edit the appropriate theme in SystemAppearance.bundle.

I made a repo with the changes here:

I know StackExchange hate linking answers so here is a summary for my case:

  1. Using ThemeEngine edit the files in
  2. The files you need to edit are WindowFrame_WindowShapeEdges
  3. Change the masks to squares.
  4. Change the base to completely transparent.
  5. Reboot or otherwise restart the Dock, Finder, SystemUIServer, etc.