: This refers to the audio specification. DDP stands for Dolby Digital Plus, and "5.1" indicates a 5.1 surround sound system. This provides an immersive audio experience with five full frequency channels (left, center, right, left rear, right rear) and one subwoofer channel.
: This stands for "web download," indicating that the content was directly downloaded from a web source rather than being ripped from a physical medium or broadcast television. WEB-DL content often offers high-quality streams. Dark.S02.1080p.NF.WEB-DL.DDP5.1.H.265-ViSTA.tar
The .tar extension means the files are bundled into a single "tape archive." You need an extraction tool to unpack them: : This refers to the audio specification
It looks like you've shared a filename for a of Dark Season 2, specifically a ViSTA encode. specifically a ViSTA encode.