What additional information should be allowed in a submission?

Question

Unlike traditional coding competition sites, submissions (answers) on PPCG are free form; the only hard requirement is that all submissions must contain the scoring header and the code that solves the challenge. While some answers stop there, others contain a lot of additional information.

Usually, additional information is a good thing. Explanation of how the code works, ungolfed code (in the case of code golf competitions), links to online interpreters, visualizations, proof sketches of used properties, etc. are always welcome, as they help understanding the post. We're still part of the SE network which strives to create valuable sources of knowledge, and although we compete rather than answering questions, reading through the submissions to a challenge is usually a learning opportunity.

It is also common to include a second solution to the same challenge in a single post, usually due to self-imposed restrictions. For example, if the interpreter of the language of choice had a bug, one may post a competing and a non-competing, higher-scoring solution. Likewise, to similar solutions where the lower-scoring one is a lot more efficient are also common.

But not all additions to a submission are welcome. An extreme example would be spam, which is deleted on sight, even if it is an addendum to an otherwise valid answer.

A less extreme example would be an ASCII art version of the code, e.g., the source code shaped like a beer bottle for a 99 bottles of beer challenge. (Thankfully, this is by far less frequent than it used to be.) While this technique is usually popular with the voters, it doesn't really improve the post from a programming point of view. Personally, I consider these additions as upvote bait.

Finally, there's this answer, which is the reason I'm starting this meta discussion. Initially, it was deleted because it contained a polyglot that solves the challenge as written in one programming language, and related challenges for other natural languages in other programming languages. This brought the submission to 1931 bytes, and it was deemed a non-serious contender.

Since then, the answer was edited to include a 24 byte submission in BASIC, which by itself is a proper answer. However, the answer still contain the information of the original revision, which occupies the lion share of the post. While I consider the polyglot quite interesting and impressive, it is only tangentially related to the challenge and takes up a lot of space. The code that solves the actual challenge seems a mere formality in comparison. For the time being, I have undeleted and locked the answer.

So:

1. Should this specific answer stay as it is, or should the second part get removed?

2. In general, what kind of additional information should be allowed as part of an answer?

3. If an answer contains irrelevant information, what should we do?

Answer 1

I'm not going to answer all three questions in one post, because then interpreting the votes is impossible. So this only really addresses question 1:

In this specific case, the added BASIC code should have been a new answer. It's not an improvement to the original answer, because it uses a different language; and it's not a trivial port which just serves to supplement the original answer. Therefore the net outcome should be the same as if the BASIC code had been posted as a new answer: the original answer should stand or fall on its own merits, and since it fails one of our basic criteria it should be edited out.

Answer 2

Can I have a word?

If my post should be deleted from there anyway, I might… instead put there the link to a third-party website where the actual answer will be stored. Is that accessible?

But in that case, I want my published answer have a header plus all my screenshot images, and first three my original paragraphs (up to actual polyglot code), since they resemble the beginning of the challenge question itself.

Then a problem that my post is just too long will be solved. Also I could provide a screenshot of the text and put it as a link.