Need a help

Hello i'm new to programming environment and i just want to ask what kind of declaration is this

"unsigned char KeyDebounceOver :1;" ?

https://en.cppreference.com/w/cpp/language/bit_field

Thank you so much can u also tell me how to declare a bit field in arduino

Just like described in the link I gave you, the Arduino uses C++.

On some Arduino platforms there may be a attribute((packed)) necessary to stop any alignment.

okay thank you