This means the file was "Downloaded from the Web" (like Amazon, iTunes, or Crackle) rather than ripped from a dusty DVD or recorded from a TV broadcast.
The resolution. While The Pitts aired in 480i (Standard Definition) in 2003, this indicates a modern upscale or a high-definition pull from a streaming service. thepitts01e01700am1080pwebdlx2656ch full
Likely a reference to the "700MB" file size standard (though slightly altered) or a specific release group’s timestamp. This means the file was "Downloaded from the