Maybe he means that Xinu is Unix backwards.

He is pointing out that leaving out "is" in "GNU is not Unix" is pretty lousy way to make an acronym (if that could be called acronym at all), as "is" is as much word as "not" or "Unix" are and omitting it is arbitrary. It isn't a preposition or something.

Removing one and two letter words from acronyms is commonplace.

Yeah, you mean prepositions, which "is" isn't. I don't really care, btw, just clarifying what parent (probably) tried to say.

> Yeah, you mean prepositions

No I don't. See https://en.wikipedia.org/wiki/Acronym#Numerals_and_constitue... and also https://en.wikipedia.org/wiki/Etiquette

It's a recursive acronym that is also UNIX backwards:

XINU

Is

Not

Unix