TFA is in reference to actually Reading TFA or RTFA. Historically, it has very strong roots in Slashdot culture, which was sort of the Hacker News of the late 1990s and all of the 2000s. By using TFA, somewhat indicates you RTFA, as opposed to everyone else who is just speculating on the content of the linked article (didn't RTFA).

Some of us here have been using terms like RTFA and TFA for twenty years, maybe longer.

HTH.