[jasode]

>I think a lot of the time "SPA" vs "MPA" essentially actually means "does the client largely render it's own HTML" or "does the server render HTML and the client just displays it".

It seems like there was already terminology of CSR-vs-SSR (client-side vs server-side rendering) to differentiate that so there was no need for SPA-vs-MPA to overlap with CSR/SSR to try and make the same distinction.

>Whether it displays that with a full _page_ refresh or by injecting HTML via Javascript does not in practice matter.

It seemed like the 'P' in SPA-vs-MPA is literally about the Page(s) being reloaded. It's "single page" or "multiple pages". That's why developers like to clarify that Next.js -- even with SSR HTML hydration of various subpages -- is still an SPA because the page on the client-side browser isn't reloaded. I just did some skimming of various "SPA vs MPA" search results and none seemed to use those acronyms as a way to classify CSR-vs-SSR. (https://www.google.com/search?q=spa+vs+mpa)

I'm also not clear how you classify Mcmaster.com ? Is it an MPA to you?

>If your definition of "MPA" is "every interaction requires a full page load", it's a pointless discussion,

No I'm not saying every interaction. I was responding to your original suggestion of "MPA with query parameters to a results page" ... and showing how McMaster.com search filters do not work the way you recommend it should. Each click of navigation and filters triggers a JSON payload and dynamically rebuilds the DOM tree. The browser's performance.timing.loadEventEnd property value does not change.