Defense of the Ancients 2 that is quite possibly legacy code for what would have been used in Half-Life 2: Episode Three.
The evidence comes from some code that appears in a folder named "ep3". Assuming the "ep3" refers to "Episode 3", the data within that folder takes on a new meaning.
The lines of code list:
/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
The flamethrower and icegun are straightfoward enough, but a "weaponizer" for concrete, liquid and metal? Either it's a weird weapon, or, more likely, damage effects for certain types of material surfaces.
Is Half-Life 2: Episode Three alive, or is this just dead code from an abandoned game?