It's bizarre that neither the README nor the associated minimal site explains what it does in detail, with screenshots or anything. I'm assuming this is a modern version of GDI++, which a decade ago brought Mac-style font rendering to Windows, but stopped being maintained a while ago. For people who aren't aware of the difference, it's essentially that Windows uses heavy font hinting to try to align character strokes…
It's wild to me that on both Windows and OSX that something that is obviously just personal preference is baked into the operating system, with no method for changing it. It's on the same level as having an operating system that didn't let you change your desktop background.
What if I want my taskbar in the middle of the screen instead of the top or bottom?
What if I want textboxes to have flashing orange outlines around them?
What if I want the close button to be blue instead of red?
What if I want the Finder face to be a sad face instead of a smile?
Customizability needs to end at some point. Technical details about font rendering is not important to 99+% of users and is only confusing.