When exporting some org file to html with `C-c C-e h o' orgmode always wants to open the html file with `sensible-browser'. Since my two (graphic) browsers reside in ~/bin I have no alternatives for sensible-browser. Which is fine by me. I don't want to change this.
What I really would appreciate is if orgmode took care of `browse-url-browser-function' (which is set to `browse-url-firefox'.) Which it usually does (in *.org files) but not while exporting.