Downright — a native TextKit 2 Markdown editor and reader for macOS

I’ve been building Downright, a free, MIT-licensed Markdown editor and reader for macOS. It opens ordinary files in place—no vault, import step, account, or sync service—and the interface and renderer are AppKit and TextKit 2 rather than a web view. The main constraint is that the Markdown on disk always stays authoritative. The rendered document maps presentation back to source ranges, so selection and edits can move between Document and Source views without maintaining a second copy of the fi...