The framerate might be limited to 60 fps, but it's not VSync (and I clearly get tearing, which is impossible with VSync). VSync doesn't actually work with borderless window mode, which
the game uses by default on windows unless you force Direct3D 9 mode.
If you want to enable it, you need to force D3D9 mode (see link above) and turn it on in the NVidia control panel.
If you want to disable it, you don't have to / can't as it's already off. If you're on Linux I have no clue, but I'd assume you'd have to cruise around the graphics driver options as you would on windows...