LGL Keychron Helper needs one-time permission to access this device's USB firmware-update mode. This installs a narrow rule that grants access only to devices presenting a USB DFU bootloader interface, not broader admin access to your system.
Note: if you are happy to continue, click Install Firmware Update Permission and you will be presented with your usual authentication window.
Approve the system prompt to continue.
Please unplug and reconnect the device, then try the firmware update again in Launcher.
This can happen if your desktop session has no permission-prompt tool available. You can run these commands in a terminal instead: