Indicates the source of the video was a high-quality Blu-ray disc.

The file format (Matroska Video). MKV files are popular because they can hold multiple audio tracks and subtitle tracks in one file. How to Play the File

Files from third-party sites like the one mentioned in the filename can sometimes carry risks:

Originally in Korean. The file name indicates it may include a Hindi dubbed audio track along with the original Korean audio. Understanding the File Specifications

This is a watermark or tag from the website where the file originated.