Meaning of mavlink message timestamps

Regarding the timestamps of mavlink messages - what exactly do they mean?
For example, take the Attitude message - does the timestamp refer to the time the mavlink message was sent, or to the time the attitude measurement was made?


Some refer to the measurement time, some to the time the data was sent… you need to look at the source code.
In a perfect world all would be time of measurement… but the world is not perfect (yet) :slight_smile: