I know people who were working on, what is now called, Libra at FB more than a year ago though. The paper was published a year ago. This just looks like a case of multiple people having the same idea.
"The adjacent possible is a kind of shadow future, hovering on the edges of the present state of things, a map of all the ways in which the present can reinvent itself."
(Whatever the hell that means.)
Even though the concept is much simpler: "adjacent possible" is the set of things within reach. Or: all the things on the border between what we have, and what we could have.