The update to the following article hints that we should be careful about the Ep3 info for a moment, but the Dota 2 part of the leak is certainly real!
OMFG HATS?! IN DOTA??
Lastly, here is the supposed HL2E3 leak:
"/src/game/server/ep3/weapon_icegun.cpp /src/game/server/ep3/weaponizer_concrete.cpp /src/game/server/ep3/weaponizer_liquid.cpp /src/game/server/ep3/weaponizer_metal.cpp /src/game/server/ep3/weapon_flamethrower.cpp" If it is real we could see an ice gun, flame thrower, and a... weaponizer in Episode 3. The big news here seems to be evidence of Dota 2's hats and Ep3 info. Shitty wizards...