Do you understand this?

[Richard Stallman]

Here's some text in man/url.texi that I don't understand.

    HTTP allows specifying a list of MIME charsets which indicate your
    preferred character set encodings, e.g.@: Latin-9 or Big5, and these
    can be weighted.  This list is generated automatically from the list
    of defined coding systems which have associated MIME types.  These are
    sorted by coding priority.

I am not sure what "these can be weighted" means, or what is
generated from what.  Can someone please clarify this?