(Since you almost need a magnifying glass to see the small purple fields in the rainbows of the flags of El Salvador and Nicaragua, I think they barely count.)
The original flag from 1978 had the sisserou parrot looking the other direction, and a different color order in the cross:
The current flag dates from 1990 (apparently also adopted November 3).
It a cool flag, but the complexity of that charge is bothering me. I feel like it could be simplified with a single green star behind a purple silhouette of the bird