Whether it needs to be maintained for the lifetime of kf6 depends if we manage to port every dataengine beforehand.. but is probably something that can be dropped during kf6 lifetime

We cannot drop things during the KF6 lifetime, by definition. Deprecate, at most, but not remove. So it will need to be maintained for the whole KF6 lifetime unless you start porting away from it, document how, deprecate it, and remove it after KF6 branching...

This is very similar to the reason we kept kdelibs4support around for the whole KF5 lifetime.

So it will need to be maintained for the whole KF6 lifetime unless you start porting away from it, document how, deprecate it, and remove it after KF6 branching...

Yeah, but then there it does not make that much sense to move it in a deprecated lib.

Or one could say that it is a plasma-internal lib, meaning we can drop it during Plasma 6

@mart Is there anything left to do here?

https://invent.kde.org/plasma/plasma5support is a thing now, containing the dataengine stuff