The identifier appears to be a specific file name typically generated by Telegram's internal servers when a video is uploaded or shared.

Since this is a system-assigned name, the actual video content could be anything—a movie clip, a personal recording, or a meme shared in a group. About MKV Files

MKV is the "nesting doll" of video formats (named after the Russian Matroska dolls). It is widely used for high-definition movies because it can hold multiple language tracks and subtitle files that you can toggle on or off.