The Grayjay app includes an entire development environment for plugins.
No idea why the keyboard app is “large”. Could it be for support on obsolete Android devices where they’ve needed to re-implement missing APIs and features entirely themselves (like Firefox/Fennec and the Share menu)?
They could also be using completely different local AI tooling, or a custom trained model that has a higher space footprint compared to other similar apps. As always the true answer lies in the available code…
Edit: Grayjay’s = The Grayjay
Curious about this one too