I assumed that Gboard spell checker contacted servers constantly and have it switched off for whatever good that does. I recently tried enabling it to play with other options and noticed that it works when my phone is entirely offline.

Does anyone know if it works locally or does it just send a bunch of data out once I give it internet access again?

Bonus question: Does anyone know of a privacy respecting spell checker for android? It looks like Florisboard can work with Hunspell through Nuspell but not on Android. Is that right?