Searching for implementations of content-language header

Hi,
in progressing the content-language draft (the part of RFC 1766 that wasn't 
just defining language tags) to Draft Standard, I need to know about 
implementations.
I know about the HTTP implementation report, but would like to know about 
usage outside of HTTP. (Verification of usage in HTTP is welcome too!)
All protocols that use 822-like headers welcome - feel free to forward this 
request to relevant mailing lists!
In particular:

- Content-language usage
- Accept-language usage
        - With quality factors
        - Without quality factors
- Usage of content-language/accept-language in negotiation

Please send to me privately; I will collect, and send the summary to 
ietf-languages.
The draft is draft-alvestrand-content-language-02.txt

Thank you!

           Harald