This is the video codec used. It was extremely popular in the 2000s and early 2010s for compressing movies into small file sizes (often around 700MB to 1.4GB) while maintaining watchable quality on standard screens.
While that specific file string is associated with peer-to-peer sharing, you can find Inherit the Wind (1960) through several official channels: Inherit.the.Wind.1960.BRRip.XviD.MP3-RARBG
The source was a "Blu-ray Rip," meaning the video was transcoded from an existing high-definition Blu-ray release. This is the video codec used