I was reading this article about the difference between は and が, and in the end of it there was this sentence: 以上が「は」と「が」の違いについての解説でした。
I'm trying to understand it based on the article itself, and I don't see any good candidate. For example, it doesn't seem to be the "new information" one because the reader supposingly would read all the article, so there's nothing new there. But maybe the author wanted to make known the end of the article saying that what was above was the explanation, and that would be kind of a new information...? The "target-が" also doesn't seem to be the case, because it's not being used with adjectives or verb expressing ability or possibility, etc. So it could be the "exclusion-が (排他)" or "が used to express phenomenon the way it is (現象文)", but I'm not sure.
Usually, when が is used instead of は, if you use は it would create a contrast sentence, but in that case, it seems that using は would only create a topic. Is that correct? If so, why would I use が in that kind of sentence?
That kind of construction appears a lot in literary works, and I always feel that I didn't understand it correctly.