--DWITH_OXYGEN=(ON|OFF)
- Install the parts of the Oxygen icon set Quassel uses. Oxygen is the default
- icon set for KDE4, and thus already available on systems where KDE4 is
- installed. By default, WITH_OXYGEN is ON iff WITH_KDE is OFF. If you are
- sure that you have the icon set already installed on your system regardless,
- use this option to disable installing the bundled icons.
+-DWITH_BUNDLED_ICONS=ON
+ Quassel requires a number of icons that are part of the KDE/Plasma icon themes
+ Breeze and Oxygen, but are generally not supported by other themes. In order
+ to avoid missing icons, Quassel bundles the subset of icons it uses from the
+ afforementioned themes, and uses that as a fallback if the system theme does
+ not provide a required icon.
+ If it is ensured that Breeze and/or Oxygen are installed on your system (e.g.
+ through package dependencies), this option can be turned off to save less
+ than 2 MB of disk space.
+
+-DWITH_OXYGEN_ICONS=(ON|OFF)
+ Support the Oxygen icon theme. Oxygen was the default theme in KDE 4, and
+ also the bundled icon theme in Quassel before version 0.13. Since the move
+ to Qt5, the more modern Breeze icon theme is preferred, and thus Oxygen
+ is disabled by default when building against Qt5.
+
+-DWITH_WEBENGINE=ON
+ Use WebEngine for showing previews of webpages linked in the chat. Requires
+ the QtWebEngine module to be available, and increases the client's RAM usage
+ by *a lot* if enabled at runtime. Only available for Qt5. The default is ON.