Background
Accidental Tech Podcast (ATP) is a long-running, highly respected podcast about Apple, software engineering, and tech culture, hosted by Marco Arment (creator of Tumblr and Overcast), John Siracusa (a legendary Apple commentator and programming language expert), and Casey Liss (an indie iOS developer). This is a "members-only special" — bonus content for paying subscribers ($8/month or $88/year).
"Mac-assed Mac app" is a term of art in Apple-nerd circles, popularized by John Gruber of Daring Fireball. It refers to a desktop application that feels native to the Mac platform: it uses standard Mac interface conventions (menu bar, keyboard shortcuts, window management), respects system preferences, supports drag-and-drop, and generally feels "at home" on macOS rather than like a ported iOS app or a cross-platform toolkit (e.g., Electron) app. The distinction has grown more salient since Apple moved to its own silicon (M-series chips), which made iOS apps runnable on Macs — and highlighted how many don't feel "Mac-assed" at all.