There is even an IANA RFC for three-letter acronyms (TLAs) (RFC5513), which says:

“For our usage, we also allow digits within a TLA. Thus, P2P is an
acronym meaning Purchase to Pay [URL-P2P]. The digits 2 and 4 are
specially used by clever people who have noticed that, when spoken,
they sound like the words ‘to’ and ‘for’. Whether this is helpful
may be left as an exercise for the user considering the brief
conversation, below.

A - Do you use the Internet Streams Protocol?
B - Yes. Do you use ST, too?
A - No, I use ST2.
B - That’s interesting. C uses ST2, too.
A - I have a car horn application called Toot-toot.
B - Really? Do you use ST2 to Toot-toot, too?”