What is the difference, if any, for machine-readers semantically correct HTML5 standard for wrapping article/section inside section/article?

Question

On various pages there are endless examples of both practices. Some do it this way others prefer it the other way. I'm asking about objective, verifiable sources about the difference between the two:

A) What are the implications, if any, if one puts <section> inside <article>?

   <article>
     <section><p></p></section>
     <section><p></p></section>
     <section><p></p></section>
   </article>

B) What are the implications, if any, if one puts <article> inside <section>?

   <section>
     <article><p></p></article>
     <article><p></p></article>
     <article><p></p></article>
   </section>

I'm not asking "what's best practice" because everybody must decide that for themselves and each project is different. I'm merely asking what exactly happens for non-human, machine-based interpreters (such as web browsers, Google crawlers, etc) as they read the page automatically, trying to figure out what goes where semantically. The answer should touch upon (and teach about) the following and provide argumentations or sources:

1. Does it make any difference to web-browsers and Google crawlers when they see article > section or section > article ?
2. If it does make a difference, then what are the implications precisely?

---

Section > Article

---

Article > Section

Answer 1

The answer is completely dependent on the content at hand. If you provide a summary of your specific content, I will update this answer accordingly. Until then, a catch-all answer:

• An <article> element is meant for content that is a "self-contained composition in a document, page, application, or site, which is intended to be independently distributable or reusable".

• A <section> element is just for delineating sections of a larger sectioning root, such as <main>, <article>, or even <footer>.

A good example of when to use section > article would be the dessert section of a restaurant menu. As a whole, it's a section of a broader document, and each dish it contains is independently distributable:

<main>
  <h1>Menu</h1>
  ...
  <section>
    <h2>Desserts</h2>
    <article>
      <h3>Ice Cream Sundae</h3>
      ...
    <article/>
    <article>
      <h3>Chocolate Brownie</h3>
      ...
    <article/>
  <section>
</main>

A good example of when to use article > section is when you have a recipe (that's independently distributable from the rest of the page) and has multiple sections which aren't independently distributable:

<main>
  <h1>Recipes</h1>
  <article>
    <h2>How to Bake a Cake</h2>
    <section>
      <h3>Gather the ingredients.</h3>
      ...
    </section>
    <section>
      <h3>Preheat the oven.</h3>
      ...
    </section>
    ...
  </article>
</main>

There are even situations where section > article > section is appropriate, or article > article > section, or any combination of the above.

It's all dependent on the content. There is no universal answer.