It is not necessary to know any of the details of how negotiation actually takes place in order to use Apache's content negotiation features. However the rest of this document explains in detail the algorithm used for those interested. In some circumstances, Apache can 'fiddle' the quality factor of a particular dimension to achieve a better result. The ways Apache can fiddle quality factors is explained in more detail below. Each item can have an associated quality factor.
Variant description can also have a quality factor.
Each item can have a quality factor. Variants can be associated with none, one or more languages. Variants can indicate a charset as a parameter of the media type. This algorithm is not configurable. If the Accept header for any dimension means that this variant is not acceptable, eliminate it.