[buescher]

And technically (the best way, right?) there's a whole thing to suss out between AppleTalk, 422, and LocalTalk, hahahahahah, but it's effectively as proprietary as PS/2 ports were, until they weren't. And ADB was 100% proprietary iirc, but I'm not going to look it up for you.

[kalleboo]

TBF, Apple did publish public standards for LocalTalk and AppleTalk and there was third-party hardware that implemented it (including stuff like switches that Apple never implemented themselves)

ADB was definitely proprietary, but arguably it wasn't a data port, nobody used ADB to output data.