> How does configuration works? Is it just configurable through the webinterface or can I update/set workflows with some external script?

Primarily Web interface. Though, the CommanderAgent can configure and trigger other agents. You can use that in combination with your external script for configuration.

> Is configuration saved in textfiles which I can put under versioncontrol and backup, or is it some unaccesable binay blob?

Agent configurations are stored in the database and can be exported as text files for your backups.

> How much does it break with each update? And how often does it receive bigger and smaller updates?

Making sure updates don't break existing installations is one of the top priorities of maintainers. Most of the updates are small/incremental. And I haven't had any problems with the updates breaking things.

> How does this compare to something like home assistant or node-red, if you know this software.

I looks at node-red years ago and determined it wasn't as mature of a project. Things could've changed since then. And I haven't heard of home assistant.

> Anything you consider missing or lacking on some area?

The UI is a bit basic. Though, I think this can also be looked at as a feature instead of a flaw.