Mavericks are taken to be unconventional and outside the norm.
The origin story of the word refers to a person: Samuel Maverick obstinately refused to brand his cattle as was the way back in the Wild West.
An unbranded steer was hailed as "oh, that is one of Maverick's". From there this sentiment: Branding signified ownership, being unowned meant being unconventional.
The true story of why Maverick was unconventional may be more mainstream: He was just plain too lazy to do so.
He did not care about the 400 cattle he got as part of a debt settlement and ignored them.
That may be the legacy of a true Maverick: To ignore the problems others think you must have.