PC Map modification? Just curious how it is done?

Are the various maps listed arrived at by dyno tuning?
It's not something I'm likely to ever undertake, but I was curious how a map such as Cozye's was developed.

Most are developed from a dyno tune, yes.   Some are hand crafted but a dyno tune is the only way to get is as right as possible.

these days more and more are going to come about from pc5's, crafted with autotune.

IIRC, Cozye's map was done carefully and with deliberate testing using a seat-of-your-pants-ometer.  Most dynometer shops are set up to make maximum HP on your literbike/hayabusa and may not provide a remotely smooth map at part throttle and lower RPM conditions.