>>
Is this JQuery JavaScript being implemented through "Add JavaScript to Storefront" in uStore?
That was indeed the purpose, as the uStore page that hosts the feature is still a "Legacy" page (ASP), including with uStore 25.3.
>>
How is this code being introduced in the development of your storefront?
Maybe I do not understand the term "introduced"?
The uStore code (from XMPie) sort of "injects" "Store JavaScript" into all Legacy pages (ASP); i.e. per instance the Login page, all pages in the "Little Man" tool, all pages that are located after the Shopping Cart (not the Shopping Cart itself in version 25.3), and the Customization Wizard page, should a Custom Legacy Dial exist.
Meaning that, all other pages (the "Welcome" page, the Shopping Cart page, etc.) are now in ReactJS (AKA "NG"), so the XMPie code does *not* "inject" "Store JavaScript" into them.
The day XMPie would release a new version of uStore, where a given Legacy page would become an NG page, then the features currently implemented as "Store JavaScript" would need to be re-developped, as part of a Widget or a Custom Theme feature, I suppose.