Just a few suggestions:

• If it's possible, we could have a short primer of what LGPL (and MIT/BSD) licenses would allow them to do (usually in commercial/proprietary contexts) and link to it both in the apidocs front page (https://api.kde.org/frameworks/index.html) and in the wiki (https://techbase.kde.org/KDE_Frameworks#Guarantees_and_License). We should probably also link to more authoritative legal references they can point their lawyers to.

• Perhaps we could list each framework's license on the front page of the apidocs so that developers/consumers will be able to tell at a glance what frameworks may or may not be appropriate for their situation.

I think the goal must be to have some machine readable license information. Ideally, this would be in the repository yaml files and then can be used both for documentation as well as for automatic checking that the source code in the repository is really compatible with that license.
The main problem IMO is though that we have several repository with a historically weird mix of licenses, even when only looking at the contained libraries, plugins and executables. So, probably we will get to a list of possible binary artifacts of that repository and for each a possible outbound license that artifact can be used under (e.g. when something is both usable as LGPL 2.1 or LGPL 3.0).