- I don't know; you might have to ask that question at https://forum.sparkfun.com/ if you don't get answers here.
- look at the example that comes with the library (SparkFun_Qwiic_RFID_Arduino_Library/Example1_Read_Tag_Basics.ino at master · sparkfun/SparkFun_Qwiic_RFID_Arduino_Library · GitHub); the tag variable is declared as a String (with capital S).
- Because tag is a String, you can use
if (tag == "someTag")