Well first off it is not used with Serial1 but with Serial0 as the label says.
Otherwise yes:- the 1 in the grey box is the physical pin number and as such is something you never refer to in code. Perhaps the only use is in wiring diagrams, but again is rarely used in the Arduino world ether mainly because different versions of the Arduino have different physical forms. For example the Uno has no simple physical scheme numbering you can follow. Also where as you can have a pin 0 in software, you can't have a pin 0 as a physical pin.
The Green boxes containing the GP0 numbers are what you should use in your code and are the same as Arduino Pin numbers.
Other boxes are alternative uses for the pin number. So you will see you can have serial communication coming from pins 0 & 1 or 16 & 17 or 16 & 17. Note how pins 0 & 1 are a stronger shade of the colours on the other pins, this indicates that these are the default pins. Using the faded colour alternative pins means to need to specify the pins you want to use.
The same goes for the two I2C buses, pins 4 & 5 are the default pins for I2C bus 0, with alternate pins meaning you have to specify them. Note here how there are no default pins for I2C bus 1, if you use that bus you have to specify them.