2.1.65 [W3C-HTML51] Section 4.10.22.5 Selecting a form submission encoding

V0204: UTF-8 is used in form submission even if accept-charset contains other encodings that can encode the entire form data set

The specification states:

 ... Selecting a form submission encoding
  
     If the user agent is to pick an encoding for a form ...

EdgeHTML Mode

UTF-8 is used in form submission even if accept-charset contains other encodings that can encode the entire form data set.