The current KDE help is built up to contain the anchors to its topics in the following way

help:/<appname>/<anchor>.html (for separate pages)

example:

https://docs.kde.org/trunk5/en/applications/dolphin/using-dolphin.html

or

help:/<appname>/<anchor1.html#anchor2> (for sections)

example:

https://docs.kde.org/trunk5/en/applications/dolphin/location-bar.html#location-bar-bread-crumb

It is impossible to build such schemes with the current code. It works only for schemes help:/<appname>/index.html#<anchor>. This scheme is nowhere to be found in our current catalog.

1. Compile and install some application with two non-empty arguments in the KHelpClient::invokeHelp call (e.g. Kalzium from git/master).
2. Open a page with the "Help" button (Tools -> Perform Calculation in Kalzium). Push the button.
3. The corresponding page of the manual should be opened.