“Input UI” was one of the original names discussed. But the plan is to add more things to that section over time. Ability to add template sensors via the UI is something being looked into for example.
So “Helpers” was decided as a better catch-all (or generic as you put it) name that is also simpler to understand for most. It will cover anything that helps you build automations, not just input controls.
Make sure that you have either default_config: or the other input domains in your configuration.yaml file.
Thank you. Adding default_config: to configuration.yaml solved it.
But I wonder why this wasn’t in there already? (I cannot recall ever having removed it)
Glad that worked for you. default_config: is a relatively new thing, it was added about a year ago. If you installed Home Assistant before then you wouldn’t have it in your configuration.yaml file.