This is the file extension for Matroska Video . Unlike MP4, MKV is a "container" format that can hold an unlimited number of video, audio, picture, or subtitle tracks in one file, making it the preferred format for high-quality movie releases.
The string you provided, is a standard release title used in the digital distribution and file-sharing community. While it may look like a jumble of characters, each segment contains specific technical data about the media file. Nikamma2022720pNFWEB-DLDDP51x264- 9xmoviespromkv
In short, this string tells a user that the file is a copy of the movie Nikamma (2022) , sourced directly from Netflix with Dolby Digital 5.1 surround sound , encoded using the x264 standard, and distributed by the group 9xmoviespro . This is the file extension for Matroska Video