Ask HN: Accessibility API Resources for macOS

Hi HN, I need to work on some features of a macOS app that would require the use of accessibility APIs, specifically reading text out of various apps. This is an area of macOS development I don't know anything about, and I'm wondering if any of you here can point me in the right direction. Blog posts, articles, books, documentation or open source apps that do something similar etc.

Thanks a lot.