"Developer commentary" refers to explanations or insights provided by the creators of a video game or software about its design, development process, and features. Full definition
The video contains plenty of in - game footage from the title, along with developer commentary on everything from setting and combat, to item management. (brutalgamer.com)
The console versions will be much the same as the PC version, but will also include 90 minutes of developer commentary. (egmr.net)
They just released a new version of the trailer, including developer commentary. (gamerassaultweekly.com)