I suppose looking it up is completely out of the question.

(It's not a joke.)

He’s not joking. Later in the first page, Siracusa says

‘Mavericks is the first California-themed release of OS X, named after "places that inspire us here in California," according to Craig Federighi, who says this naming scheme is intended to last for at least the next 10 years.’

And the words “California surfing spot” in your quote link to http://en.wikipedia.org/wiki/Mavericks_(___location), so that is the name of the place. I guess it’s just coincidence that “maverick” is also a word.

It's named after a dog called Maverick. I'm guessing they made it plural to refer to the waves themselves.

Or it was "Maverick's", misspelled.

Yes, he should have written "an awkwardly plural-esque possessive". Siracusa, I'm disappointed by your inattention to detail!

http://en.wikipedia.org/wiki/Mavericks_%28location%29 ?

It's named after Tom Cruise in Top Gun. Duh.