It started out as a mod and slowly moved into an individual program. I believe right now they are breaking free from the main Source line so they don't have to update with every new Source version. It just calls in assets from other games you have installed now.
I would say its a game, because you cant really sell a mod, now can you.
tfc was a mod and they sold ita lot of mods for quake were sold :v
Its a game/mod.Used to be a third party mod where you had to have a source engine, now it is its own game.
It's a mod and a game. It is an existing mod, but also a retail game.