If you aren't sure what's inside the file, don't worry. MKV files are generally safe containers. To view it:
It supports high-quality video and advanced features like multiple languages or chapters. AgADVggAArAnwFY.mkv
This specific filename, , follows the naming convention used by Telegram when a file is saved without its original metadata or when downloaded via certain bots. If you aren't sure what's inside the file, don't worry