Technical References - [getmimeheader]

Displays a specific MIME header

[getmimeheader name=headerName]

Putting [getmimeheader name=HTTP_ACCEPT_LANGUAGE] in your template displays the value of the MIME header called "HTTP_ACCEPT_LANGUAGE" which is a code representing the human language that the viewer is able to read. Use [listmimeheaders] to see all the headers your browser is sending.