video – Where are GoPro Highlight Tags stored?

I want to extract the (manually set) highlights from my GoPro-footage (HERO6-Black).
I want to do this to mark the highlights on vacation and can use them to edit in Premiere Pro later.

I found that the Highlights are stored in the mp4-file. So a simple parser that extracts all highlights with a timestamp would be the goal (preferably in python).

The answer to this Question
suggests they are stored in the mp4-header (udta box).
I used a HEX-Editor to find the suggested box but couldn’t find anything. Having said this I’m not super familiar doing this!

As the other Question is more than 5 years old they mybe changed something?

I’m also aware of the GPMF ( but I could not find anything about the highlights, just the sensordata.

I also foud this:
but I think it refers to the highlights set in the GoPro-Quick software which don’t get saved in the mp4-file.

I would appreciate if anyone has an answer or an idea on what I could test.
Thank you 🙂