Where is PAIFG_L defined?

From looking at msp430f5529.h

/* External references resolved by a device-specific linker command file */#define SFR_8BIT(address)   extern volatile unsigned char address
...
SFR_8BIT(PAIFG_L);                            /* Port A Interrupt Flag */

Where is that command file? And what is portA? I don't think my launchpad has anything marked port A?

Thank you