What's a file named 'hl3.txt' doing in Dota 2's latest update?

Hl3

Um, what's this, Valve? SteamDB noticed some interesting new files added to Dota 2, and we've downloaded them and verified that they exist. The files are: hl3.txt, rpg.txt, and ai_basenpc.txt.

Here's a line from hl3.txt:

string m_HelpText = "Combine Pulse Ceiling Turret"

The files, which appear to be help text for a development tool, also refer to vehicles, NPC behaviors, squad behaviors, ziplines, and quests. Here's another example:

string m_HelpText = "NPCs that are in the same squad (i.e. have matching squad names) will share information about enemies, and will take turns attacking and covering each other."

Are these just some old files that were misplaced and have nothing to do with anything, or do they have to do with Dota 2? Or are they actual files related to the development of Half-Life 3? Here are the files so you can look for yourself: hl3.txt / rpg.txt / ai_basenpc.txt.

Fox Mulder was unavailable to comment, but a spokesperson for the FBI tells us that he wants to believe.

Tyler Wilde
Executive Editor

Tyler grew up in Silicon Valley during the '80s and '90s, playing games like Zork and Arkanoid on early PCs. He was later captivated by Myst, SimCity, Civilization, Command & Conquer, all the shooters they call "boomer shooters" now, and PS1 classic Bushido Blade (that's right: he had Bleem!). Tyler joined PC Gamer in 2011, and today he's focused on the site's news coverage. His hobbies include amateur boxing and adding to his 1,200-plus hours in Rocket League.