When splitting phosh-osk-stub out of #phosh one of my goals was "use it from day one". This required to hack in a virtual-keyboard driver so Electron apps (and other apps that can't deal with text-input-unstable-v3) can fall back to "emulated key presses" instead of using an input-method.
Prompted by input from Kai Lüke who (rightly) pointed out that the German layout was missing symbols in virtual-keyboard mode I revisited the situation and we can now handle more languages:
1️⃣ /2️⃣
Note that other on screen keyboards handle that well since a long time and that this really only affects the fallback to virtual-keyboard mode.
GTK apps using text-input-unstable-v3 don't care as they handle unicode via text-input so they worked well before and can even benefit from text completion.
2️⃣ /2️⃣
