It is hard to see relevant primary information about calib3d module.

1. It starts from the misleading link on fisheye.
   

2. Relevant detail about pinhole camera model is somewhere in the middle (page 12)
   

Current proposals are:

1. try to move details on the top of the page
2. add subgroups for better structuring of information (calib3d contains hand-eye algos too, but all of them are in one place)
   Good examples are imgproc, videoio modules.