The string appears to be a technical identifier or filename rather than an official document title or established literary work.
If you are researching "MKV" in an academic or scientific context (as suggested by some data search results), the abbreviation may refer to: AgADnAAD2skhVA.mkv
: For example, Telegram's API uses similar base64-style strings (often starting with "AgAD") to identify media files stored on its servers. The string appears to be a technical identifier
: A single-stranded RNA virus studied in animal models for human infection . AgADnAAD2skhVA.mkv