How many I2C lines does the Arduino Due have? According to the Arduino pin Mapping

20  PB12    SDA 3   6
21  PB13    SCL 3   6
70  PA17    SDA1    3   6
71  PA18    SCL2    15  9


The first one seems pretty obvious, the second one though is confusing. They have different labels. I also do not see other SDA or SCL in the table. So is this a typo?
According to the Wire library documentation https://forum.arduino.cc/index.php?topic=132130.0:


  The Arduino Due has two I2C / TWI interfaces SDA1 and SCL1 are near to
  the AREF pin and the additional one is on pins 20 and 21.


And the table:

Arduino Due: 20 (SDA), 21 (SCL), SDA1, SCL1

So it seems in your table SCL2 should be SCL1.