AppleTalk is a protocol that was used on classic/vintage Macs (think: early/late 1980s, 1990s) to create local networks. The wikipedia page [0] has a good historical overview, including the parallel rise of ethernet / tcp/ip (which won).
Using TailTalk on my modern Mac, I can expose a file share accessible to my Macintosh Plus, which has a simulated SCSI Ethernet adapter bridged to a Pi Pico 2W's wireless connection via a BlueSCSI.
[0] https://en.wikipedia.org/wiki/AppleTalk