I found that Battlefield 3 as well as Saint's Row the Third use this texture in their final tone-mapping stage. Can anyone share a link to an article about how this texture is used?
UPDATE: As there are hardly any examples of Color Grading implementation on the net, I will post my quick and dirty sample for XNA 4.0. This does nothing but builds the default 2d colormap from scratch on GPU, copies it's contents into a 3d texture on CPU and performs the actual color-correction with the shader code from the article provided in the answer.
If you want to know what you can do with this, look here:
In short the author explains there, how you can basically make a screenshot of your normal in-game image with the default color grading palette on top, perform screenshot color correction in photoshop, cut and copy the deformed color correction palette into the engine and have that color correction applied for every in-game scene automatically.