Based on based on this excerpt from Yahoo! Style, I’d said that this writer is uber imaginative in her creation of a possessive from nothing more than a parenthetical phrase, an apostrophe, and an S:
It’s a real first! I’m pretty sure no one in the English-speaking world has ever tried to put an entire parenthetical between ‘S and the noun it applies to. It’s brilliant! Imagine how dull this would be if she used the traditional “by utilizing the ad-buying interfaces of Facebook (which owns Instagram).” Booo-ring.