Tesla Open book/Open internet Test for Mechanical Engineer

I have cleared the first round of interview in Tesla (Bay area) and the next round is a 2.5 hours open book/Open internet test is what I have been told. This is a Mechanical engineer role. Has anyone attended one such test? Can you give some advice regarding the same like test pattern, topics covered etc.

Edit: It is a 90 mins test and not 2.5hrs (recruiter mentioned 2.5hrs by mistake instead of 1.5hrs).