If you build Elisa from source but don't have qml-module-qt-labs-platform installed from something else, Elisa won't launch: $ elisa [...] QQmlApplicationEngine failed to load component qrc:/qml/ElisaMainWindow.qml:259 Type ContentView unavailable qrc:/qml/ContentView.qml:427 Type MediaPlayListView unavailable qrc:/qml/MediaPlayListView.qml:26 module "Qt.labs.platform" is not installed Now technically it's a runtime dependency and not a build dependency, but it would be nice if this dependency were expressed in CMakeLists.txt so that build-from-source users would get all the requisite dependencies. Or if that's not the right way to express runtime dependencies for build-from-source users... it would be nice if whatever right way to do it may be got done. :)
Unfortunately, I do not think there is a way to test with find_package for pure qml modules from cmake. This is the reason we have documented such dependencies in the community Elisa wiki page and the README.packagers file.
There is one thing that Elisa could do better is handling nicely (from a user point of view) errors when setting up its qml UI. Can I modify a bit your report to reflect that ?
Probably not worth it TBH. People building from source should be able to read the docs and figure it out.