Cat.s01.1080p.web-dl.aac.5.1.esub.x264-hdhub4u....

: This indicates the season number. Here, "S01" means Season 1.

Set against the backdrop of the Punjab hinterlands, the story follows (Hooda), a former police informant (a "CAT") during the insurgency of the 1980s. Years later, he is forced back into the dark world of drug trafficking and police corruption to save his brother’s life. The show is praised by critics on Rotten Tomatoes for its gritty realism and Hooda's powerhouse performance. Key Features for a Review or Feature Article Cat.S01.1080p.WEB-DL.AAC.5.1.ESub.x264-HDHub4u....

However, if you need help with:

: The audio codec and channel layout. AAC (Advanced Audio Coding) is a standard compression format, while 5.1 indicates surround sound (five full-bandwidth channels and one low-frequency effects channel). : This indicates the season number