I have made tmp solution that mounts Maliit plugin into any app running in Flatpak. This solution requires:

- flatpak-maliit-plugin-qt installed in SFOS
- app should use KDE 5.12 runtime

Just released flatpak-runner will add the plugin into container when app is running and keyboard can be used.

So, this means that we can use Flatpak applications as they are provided by KDE and Flathub. No recompile or hacking is needed. Assuming that they are QML/Qt 5.12 ...

Proper solution will be to add Maliit plugin as an extension of KDE runtime. Will talk to KDE devs about it.