Pebble seems to know a lot about you

Interesting. Not only what Pebble achieved in the last year, which is impressive against the mighty competition, but also what Pebble knows about you.

They published a picture with some remarkable information about the usage. E.g. what were the most used Emojis, or how many notifications were received.

I was not aware that Pebble can get those information. Not that this is a big deal if these data are anonymously saved. But that is the question. Can Pebble directly see which user received how many notifications are received or how many steps a user walked? Or even the content of the notification?
I assumed that the notification process is independent and would not be recorded at all from the pebble servers.

I totally trust Pebble, but this should be better known.