No, Philly Inquirer, the Barclays Center is not "about 15 acres." Not even close.

From the Philadelphia Inquirer, 8/26/20, The Sixers are targeting Penn’s Landing for a potential new basketball arena:

Harris Steinberg, who led a committee 12 years ago that helped envision what is now the waterfront’s master plan, said the Sixers’ proposal could work “if it actually contributed to the urban fabric.” But Steinberg, now executive director of the Lindy Institute for Urban Innovation at Drexel University, said he was skeptical the arena would leave public space around it to create an accessible, public waterfront.

The Barclays Center in Brooklyn, N.Y., is about 15 acres, he noted. The site the Sixers are seeking has less than 8 acres available for development. If the arena took up the entire space, he said, “they need to go back to the drawing board. This is public space and it’s designed that way in perpetuity.”

Hold on.

The Barclays Center isn't "about 15 acres." The overall Atlantic Yards/Pacific Park project, with space for 16 towers along with the arena, is 22 acres.

The entire arena block, according to the project Design Guidelines, is 315,670 square feet, as shown in the screenshot below, with space for four towers plus the arena. (Likely the B1 tower won't be built, leaving the accidental plaza.)

At 43,560 square feet per acre, that's about 7.25 acres. But the arena parcel itself, as the image indicates, is less than half that total.

Oddly, and inaccurately, the building permit says the arena parcel--not the entire block--is 325,360 square feet, or about 7.5 acres.