Having DuPont cables like on the picture...
... and the RFID RC522 reader with colored wires as found in one of the tutorials.
I know that copper is the same inside of the wires. Anyway, is there any standard or de-facto standard of assigning colors to the meaning of the pins? Black for ground and red for +voltage are known from elsewhere. But what about all the other pins? Here is the detail view for better readability: