[jerrycruncher]

Anecdotally, I'm a native speaker, have been reading text on BBSes and then the internet for well over 30 years, and have never seen that one. AFAIK has been around for decades.

Like some other commenters, I skipped right over it rather than try to parse it.

[__sdegutis]

I've been online for 20 years, and AFAIK was pretty common, although a few years ago I came across AFAICT which was pretty easy to extrapolate as ending with "can tell". From that I was able to recognize the pattern here and pretty quickly got "understand it" for UI. I think it's pretty neat that we're able to adapt language in this way, though obviously not foolproof or universal.

[ams6110]

They are all weasel words and best avoided. It's a way to make a claim that you're not sure of, with an out if you're wrong.