The HTTP Accept header can specify priority using the q specifier, such as
application/xml;q=0.8
I had a look in the RFC but could see any mention of whether the q specifier is subject to localization or not. For instance, could a European browser send the figure as q=0,8 instead if the Accept-Language was set accordingly?
If not, there must be some documentation somewhere that specifies that HTTP uses the period notation and is culture invariant in its headers I guess?
Section 3.9 of RFC-2616 (the HTTP/1.1 spec) defines a Quality Value (the value assigned to ‘q’ in your example) as:
so all HTTP applications must use a decimal point, not a comma or anything else, regardless of where in the world they reside.