: Indicates this is the second part of a large collection or bundle of files, commonly used when a single download would be too large to manage.

The filename likely refers to a compressed archive containing a "MegaPack" of content from the SG-Video project.

: This likely denotes the creator or project name. In the context of specialized video equipment and professional projects, Global Systems ( Global Systems - YouTube ) uses the "GS" or "SG" naming for professional video and audio equipment consulting .

: Frequently an abbreviation for "Screenshots," "Scripts," or "Source." Given it is paired with video content, it most likely contains high-resolution screenshots or previews of the videos included in the pack.