I see all kinds of invalid arguments passing by here and there. I think it is no work at all to keep the Dox current.

Whenever you change an existing method you change the dox accordingly. Whenever I do a commit, I almost always look at the diff before that, that is where I clean left overs from failed experiments, fix whitespaces, make a small optimalisation and adjust the apidox comments….

There is a lot of helpfull kde documentation, without it I would have never put X-DCOP-ServiceType=Unique in my .desktop while converting RSIBreak to a KUniqueApplication. Only because it was mentioned in the KDE API Reference.

I imagen the same will happen for potential new contributors of KMyBigApp. Really, it is no work at all. Just do it.