Firefox can use policies.json to customize it. This is especially useful for first-time setup where it can be tedious to go manually disable sponsored portions and install Ublock Origin.
This policy force the installation of Ublock Origin where it cannot be disabled (although uBO cannot be uninstalled, this does not prevent use from whitelisting sites; and it does not support adding custom filters). It also setup the homepage correctly, disable Pocket, sponsored stories and telemetry.
To use this, place the policies.json file into the correct location.
Windows
C:\Program Files\Mozilla Firefox\distribution\
Linux (system-wide)