[Out_of_Characte]

There is no additional mechanism, You just open text files as many times as you want with any program. (Unless I misunderstand the parent comments)

[yoz-y]

I think the confusion comes from the fact that the sentence mentions both macOS and iOS, whereas url schemes are an iOS-only concept.

[robenkleene]

Got it yeah, this is probably why I was confused. URL schemes are the only way to do a lot of things on iOS, whereas (as far as I know) they're additive to the *nix ways of doing things on the Mac.