Unlike other formats, MKV supports "soft" subtitles that can be toggled on/off and styled like a separate text file, rather than being "burnt" into the video.
You can embed actual files (like PDF scripts or JPEG cover art) directly inside the video container. fd5d2057a7e8da61796dc6d1cc243cc9.mkv
If you are investigating this file for security reasons, it's worth noting that some malicious files can be disguised with common extensions like .mkv but are actually executables or command scripts. You can verify the file's safety by uploading it to a service like VirusTotal to see if the hash matches any known threats. Unlike other formats, MKV supports "soft" subtitles that