The device is trying to pair with your computer via Bluetooth.
Pairing is the security feature to allow communication between the two devices. Trust and authorize would allow the device to pair with your computer and would in the future automatically authorize pairing
Authorize would pair the devices but you may have to select this option in the future ...
For an one-time application, you can right-click the window title bar, and select "More Actions > No Border".
If you want a particular program's window to always be borderless, you could go to System Settings -> Window Management -> Window Rules, and define a rule that will automatically make that window borderless anytime the window is created.
After trying KDE Neon, I switched to Pop! OS and it threw message that it couldn't boot because of security policies of computer. I had Secure Boot enabled in BIOS. I couldn't see the option for Secure Boot at first and had to set Boot Mode to UEFI in BIOS. Secure Boot seems to block some graphic drivers, but I am amazed how the OS booted at all!