Sounds good, thank you again for the answer! :)

That's cool! Ok great, glad it is part of this and intended to be there. Need to confirm it is not a bug or someone tampering with an add-on since I use it at work.

Thank you for clarifying!

When I was clicking on the window to maximize it, nothing happened. I could not get anything more from this than what is in the screenshot. It stayed on my screen this time for about 10 seconds, which is the longest I've ever seen it.

I captured a screenshot of it just now. I noticed the window is labeled as "Device ManageR"  just like that...  I have attached the image here.

I did not notice it until after I installed it, later in the day. What it seems to be is a sync or something that is initiated, by what I speculate is the addon. I removed the addon and have not seen the window appear again, now I installed the addon anew and waiting to see if it appears.
The window I mention is not appearing maximized, it is minimized in the taskbar. I only noticed because I have multiple monitors, and have my Firefox on my 2nd monitor. The window that appears flashes only on the primary monitor's taskbar. It remains for about 2 - 4 seconds and disappears. I do not notice this during installation, only while using Firefox and appears throughout the day even when Firefox is open, but not currently being used.