that "register_sidebar" array in my previous answer-post has been working fine ever since January 30, 2023. then suddenly on April 2, 2025 all my wordpress admin & frontend pages were broken saying "Undefined variable $i" - so i removed all the "$i"'s from the 'name' & 'id' lines and that seems to have fixed the problem.

clearnly not knowing what i'm doing but curious to know - what was the $i for & why did it work but not now?