This message is shown if your computer has detected a difference between the firmware installed on your Mac and the firmware that macOS expected to see. Firmware is software that allows your Mac hardware to work with the OS, and firmware that has been damaged or modified might affect the stability and security of your Mac.
Beginning with macOS High Sierra 10.13, your Mac periodically checks for changes to the firmware and allows you to send information about these changes to Apple.
If you see a message that your computer has detected a potential problem, click Send to Apple to transmit information about the firmware change to Apple. You can click Show Report first to see the information that will be sent. Or you can click Don’t Send to skip sending any information and dismiss the message.