In general it seems a bad idea to have two http-strings.c files as this precludes to have them both in the Contiki library. However as it stands it seems most reasonable to have one http-strings.c file be a clean superset of all usecases in order to allow them to run together in a single binary. As webserver/http-strings.c already contained strings not present in webbrowser/http-strings.c it seems reasonable to consider webserver/http-strings.c as the superset described. From that perspective it is appropriate to remove all strings from webbrowser/http-strings.c which are not used by the web browser in order to save memory otherwise wasted.
The "normal" web is moving forward quickly reducing the interoperability of the Contiki web browser to nearly zero. The Mobile Web fits the capabilities of the Contiki web browser much better. Modern smartphones don't need the Mobile Web anymore but there are large areas in world with rather low end mobile phones and limited mobile bandwidth where the Mobile Web will be necessary for quite some time.
From that perspective it is reasonable to increase the Contiki web browser's interoperability with the Mobie Web - namely WAP 2.0 aka XHTML MP. XHTML MP is delivered as MIME types 'application/vnd.wap.xhtml+xml' or 'application/xhtml+xml'. Therefore we (try to) parse the document if the MIME type contains the substring 'html' (which is true 'text/html' too).
