The FBI, like many parents, struggles to keep up with the newest digital jargon, which is why the federal agency created its glossary of terminology and acronyms.
According to Input, the FBI has its 83-page handbook of internet slang, which you can read for free on the Internet Archive.
It's worth noting that the FBI's massive encyclopedia of internet slang is a little dated by today's standards, having been obtained in 2014 via a Freedom of Information Act (FOIA) request filed by the non-profit MuckRock, whose mission is to make politics more transparent while holding the government accountable.
Along with well-known phrases like "LOL" and "BRB," the FBI's internet slang dictionary includes some weird terms like ALOTBSOL (always look on the bright side of life), BIOYIOP (blow it out your I/O port), DENT (don't bother next time), GIWIS (gosh, I wish I'd said that), and others.
You may read the instructions yourself on the Internet Archive but be warned: the resolution is quite bad, and you'll need to zoom in to understand it.
According to a story published by The Verge in 2014, when the FBI's online slang guide first became public, the dictionary of phrases was compiled by the federal agency's Intelligence Research Support Unit and was characterized as beneficial for "keeping up" with children and grandkids.
Although we now know what the FBI was searching for online over a decade ago, it would be interesting to look at the agency's more current internet slang guides, which have certainly swelled in size given that we spend so much of our everyday lives online.