The FBI knows what LMAO means. According to an internal manual released today under the Freedom of Information Act to the open-records website MuckRock, the bureau also knows what ANFAWFOS, EOTWAWKI, and IITYWTMWYBMAD stand for. So beware: The feds have cracked Twitter slang. Or think they have.

“With the advent of Twitter and other social media venues,” the manual begins, “the use of shorthand and acronyms has exploded. The DI’s [Directorate of Intelligence’s] Intelligence Research Support Unit (IRSU) has put together an extensive—but far from exhaustive—list of shorthand and acronyms used on Twitter and other social media venues such as instant messages, Facebook, and MySpace.”

The 83-page manual, which is titled Twitter Shorthand, contains “about 2800” terms, including common ones like SRSLY and SMH, less common ones like SOIDH (screenshot or it didn’t happen), and even less common ones, such as the aforementioned ANFAWFOS (“and now a word from our sponsor”), EOTWAWKI (“end of the world as we know it”), and IITYWTMWYBMAD (“if I tell you what this means will you buy me a drink?”). And so on.

Page 70 helpfully defines “TROLL” as “a deliberately provocative message board user”:

You can read the entire manual here.