The file appears to be a media file using the Matroska Video (MKV) container format. While the specific filename seems to be a generic or randomized identifier (common with files downloaded from messaging apps like Telegram or certain automated systems), the format itself is a robust, open-source standard. Understanding the MKV Format
Because "AgADZAcAAmZG6VY" is likely a unique ID, you can use technical tools to reveal what is inside: AgADZAcAAmZG6VY.mkv
How can I check the video/audio format for a MKV file? - Super User The file appears to be a media file