mediasharingd - Quick-flash popup window during startup

This started several weeks ago whereby a popup window flashes on the screen, and it happens so fast that I haven't been able to read it... or take action. Well, I had to take a video on my phone so I could playback and pause it to be able to see what it is. You will be able to see my attached screenshot of how faded it is due to the speed and how long/short it is visible on my MacBook Air M1 - I'm surprised my eye even caught it every time I started the computer.

What is mediasharingd?

So, my questions are:

1. What is it and what does it do
2. When I go into the firewall settings why it is not listed
3. How do I Deny or Allow if it doesn't stay on the screen and it auto-disappears
4. Why should I Deny or Allow - but I am not even given the option to act based upon its disappearing act
5. Why doesn't it stay on the screen so I am able to take action
6. If it is "just" an OSX process, then why does it have to even pop up in the first place
7. If it's a third party app, whose is it and how did it get there
8. But either way, is it safe
9. Should I delete it, and if so, how?

Thanks : )