Hello Christian,
I regret you will need to convert the quaternions to Euler angles manually, on the logged data. You will be able to do it in a spreadsheet like Excel. The logged data is in Comma Separated Value format which Excel will understand. Or you could use the Python CSV library.
Please be aware:
https://github.com/sparkfun/SparkFun_IC … /issues/74
https://github.com/sparkfun/SparkFun_IC … /issues/77
https://github.com/sparkfun/SparkFun_IC … -863134578
Good luck with your project!
Best wishes,
Paul