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. If no variants remain, go to step 4. Select the 'best' variant by a process of elimination. Each of the following tests is applied in order.