It was indeed LaTeX. The ACM format creates a 1" box at the bottom of the first column which contains the copyright information. The copyright information on the authors' version (yes, I see the typo in the document now) doesn't take up much space so there's a lot of white space.
The block quote itself is just \begin{quote} ... \end{quote}.
The block quote itself is just \begin{quote} ... \end{quote}.
The published version looks like this https://imgur.com/puBzzdZ