Since the filename is randomized, you cannot determine the content by the name alone. To see what is in the file, you can:
The .mkv extension indicates it is a Matroska Video file, which is a high-definition container format capable of holding multiple audio tracks, subtitles, and high-quality video. How to Identify the Actual Content
Right-click the file and select Properties (Windows) or Get Info (Mac). Sometimes the "Details" tab will contain the original title or tags. AgADtAIAAkXhEEQ.mkv
Use a player like VLC Media Player or MPC-HC , which are designed to handle .mkv files regardless of their filename.
If you received this file from an unknown source or a suspicious bot, be cautious about opening it, as randomized filenames are sometimes used to mask the true nature of content. Since the filename is randomized, you cannot determine
This specific naming convention ( AgAD... ) is a unique file ID generated by Telegram.
If you found this in your device's "Telegram Documents" or "Telegram Video" folder, it is likely a video that was downloaded but not explicitly "saved to gallery/downloads" with its original name. Sometimes the "Details" tab will contain the original
If you still have the chat, look for a video file sent around the time this file was created.