In the Technical Reference Manual for F28M35x devices (spruh22c) XINT13 is listed in the PIE Vector Table on page 116, and is shown in the CPU-Timer Interrupts diagram on page 141.
I am unable to find any information about this external interrupt anywhere. Is there a chunk of documentation missing, or are these typos? Are there any control registers for it? If not, what pin is this input assigned to?