Option is used extensively for non-Ascii characters, a comprehensive list would be quite long.

A few of the easier to remember:

option + 0 for degrees º

option + u for to place an umlaut over the next typed character (when it's a valid combination, anyway) ëüä

option + c for cedilla ç

Interesting. Kind of reinventing Compose key combos. I wonder why they didn't just reuse Compose ones from FreeBSD.

	▲	macintux 7 hours ago \| parent [-]
		This dates back to the beginning of the Mac, so it's almost 10 years older than FreeBSD. (I'm unfamiliar with other UNIX compose key tooling that may have predated it.)