TypeError: E is not iterable and script versions

I’m mostly a dabbler in the code, dangerously trying things. On an overdue update, our use of this how to (on adding a featured topics to home page) vanished.

On investigating our theme component where this is applied to the <head> I spot errors

TypeError: E is not iterable (cannot read property undefined)

I can’t find any things identified as E. For some reason, in looking through posts here I noted that many times the script tags have a wide range of versions numbers, I used the given

<script type="text/discourse-plugin" version="0.8">

but see other code with various version numbers, Sometimes 0.8, 0,.8.11, even 0.11. I am not 100% sure how this is is used, but on whim, I changed mine to 0.8.11 and BOOM, the error cleared.

I know this might be basic, but what is the use here and how does it affect my template? Thanks for some discourse 101 advice.