Which device do you have? If it's Nexus 5, you shouldn't install the patched kernel anymore as it's already installed by default. You just need to install anbox via apt.

Regarding Firefox - we would need Mozilla to build a mobile version for UT, or to have someone code a fork for one - otherwise you can already install desktop Firefox on UT devices via a Libertine container - some info on that here - https://forums.ubports.com/topic/3774/where-is-firefox/15?_=1603043940011 - but the performance and interface on it will be slower and more clunky relative to the native Morph browser. Regarding "built in mail app" - there is already a very good UT native email client being maintained available for install in the Open Store - https://open-store.io/app/dekko2.dekkoproject Dekko2 is coded and maintained by a team that is separate from the UT core developers - so it is not by default included in the OS. Also - many people do not use email clients these days, or prefer to use web based clients - so the app is not included with the UT OS image by default, in order to keep the image smaller, and with less things that might not get used by all users. Best regards, Steve Berson

Please see https://forums.ubports.com/topic/206/will-you-port-to-device-x