need to remove st sign fuse NB miata?
 

I know for NA's, you must remove the ST SIGN fuse (which I believe is located in the engine bay fuse compartment). For NB's, I believe this fuse is located inside the cabin under the dashboard. I think I read somewhere a while back that the NB's do not need to remove this fuse when running megasquirt.

Can anyone clarify?

I did not remove any fuses when putting a MSPNP Pro (MS3) in a 99 a few days ago. Started right up.
Refer to manual: MegaSquirtPNP by DIYAutoTune.com

No you do not. I don't know what it's even for, but I think it's for flashing the brake light on the dash while you are starting the car. It might also cancel cruise control.

The NA6 used it to feed power to the fuel pump till the AFM was latched on since it had no ECU control over the pump from the factory. Totally different.

Correct.

This is for 1.6 NA cars only. ('90-'93 in North America.)

It's because of how the mechanical airflow meter, the starter, and the fuel pump interact. In 1994, when the mechanical airflow meter was replaced with a hot-wire AFM, control of the fuel pump was moved over to the ECU, so the connection to the starter went away.