WTF

WTF, an acronym for Warcraft Text File, is a Blizzard file extension. The most notable of this type are config.wtf and realmlist.wtf. It is also the name of a subdirectory of the World of Warcraft directory which contains these types of files.

It is also shorthand for what the f*** or who the f***, used to show surprise, displeasure, and/or outrage at a person or circumstance.