[adontz]

This service does not look transparent at all.

How does it work? What network protocols does it use? What are configuration options? Is this vendor lock-in or I can go self-hosted?

[enatik]

It uses fairly standard HTTPS for update checking (endpoints). I'm planning to write a detailed blog post on how it works technically so hopefully that will answer your questions.

Completely self-hosted solutions aren't currently planned.