You can forward files to a Telegram Renamer Bot before downloading them to give them a recognizable name.

On mobile, instead of just downloading, tap the three dots and select "Save to Gallery" . This often triggers the phone to sort the video into your photos app where you can see a thumbnail preview.

Since "AgADigAD904IVg.mkv" is a generic identifier, a blog post about it should focus on the and how to manage them.

The .mkv extension tells us it's a file—a high-quality "container" that can hold video, multiple audio tracks, and subtitles all in one place. The long string of letters and numbers (the "AgAD..." part) is a unique ID generated by Telegram’s servers to identify that specific piece of media. Why Does Telegram Give Files These Names?