K40 Mods

Just wanted to expand the post a bit. Page 4 of the attached manual lists the ports on the board and their use.
GRBL_Controller_User_Manual_62d2cafd-0128-403c-af4b-6e43720b9b8d.pdf (1.1 MB)

Can someone provide a brief, real world example (or point me to a link) of what some of these might be used for? Items 1-13 are fairly obvious, but I’m not sure what 14-26 would be used for. I’m most interested in the PWM output signals and the temp controller signals and what I might use them for.

Sorry if these questions are basic. I’m just trying to learn as I reassemble my k40 and see if there are other modifications I should make.

Yesterday, I discovered my k40 has the plastic washers which I replaced and I had to remove paint from the chassis to ensure a proper ground as noted in the Light and Electricity page.
Thanks again