Applications outside of KDE (for example, HexChat) that use the XDG runner to open files do not use the MIME type of text/html to open up URLs -- they use x-scheme-handler/http and x-scheme-handler/https instead. For example under an old setup, HexChat will try to open a http:// or https:// url. Without the setting, it ends up running Links in X11 mode. (I've since yanked out X11 mode from my compile of Links, as I'm using Gentoo). Reproducible: Always Steps to Reproduce: 1. Set any browser in KDE System Settings to be default (say Chrome). 2. Install Links with X11 (this auto-sets a default XDG x-scheme-handler). 3. Install HexChat (it's an IRC client). 4. Open up and connect to Freenode. 5. Click on any link. Actual Results: Links is opened up to the URL. Expected Results: Chrome is opened up to the URL. KDE needs to adjust ~/.local/share/applications/mimeapps.list to put in the proper x-scheme-handler/http(s) listings.
Confirmed under KDE 4.11.3, Tanglu (Debian). In the case of Hexchat it did nothing for me until I set x-scheme-handler/http.
Cannot confirm here with KDE 4.11.10. After setting default browser to something else, then back to chromium-browser, x-scheme-handler/http was properly set. You may want to check/compare outputs of xdg-settings get default-web-browser xdg-settings get default-url-scheme-handler xdg-mime query default x-scheme-handler/http xdg-mime query default text/html
Can confirm this on system-settings 5.4.95, frameworks 5.16.0
Git commit 1193971e9a270d37970cf7799444773be68576c6 by Kai Uwe Broulik. Committed on 27/07/2017 at 10:52. Pushed by broulik into branch 'master'. [Component Chooser] Update http(s) scheme handler when changing default browser FIXED-IN: 5.11.0 Differential Revision: https://phabricator.kde.org/D6933 M +18 -0 kcms/componentchooser/componentchooserbrowser.cpp https://commits.kde.org/plasma-desktop/1193971e9a270d37970cf7799444773be68576c6