Hi Thomas,
Well, thank you for all your loyalty and support of the community (I now that you are extremely active in the KUF!).
We don’t yet have a formal process to apply for logo-reuse, but for non-commercial use, we are absolutely fine with giving you approval for it.
With the upcoming “openHAB Foundation e.V.”, the idea is actually to formalize it in the way that foundation members are automatically free to use the logo. I hope we can welcome you as a member once we get started 8-).
Cheers,
Kai