So the applications in Ubuntu Gnome 19.04 gives android style granular control over how apps integrate and work with your system
You can find this under settings, Applications section. Using this you can associate and disassociate default handlers, also fine-tune application integrations like block apps from sending notifications.
Apologies if this seems to be an incorrect query under Support and Help Requests. Let me know if I should move this question to some other category and which one it should be.
Best,
Nishit
