I am trying to understand how this works: https://www.mediawiki.org/wiki/API:Revisions

There is a parameter DiffTo which says: Revision ID to diff each revision to. Use "prev", "next" and "cur" for the previous, next and current revision respectively.

I suppose that I can give it revision ID instead of that string hint. So let's say we have 4 edits made to the page [[X]], their ID's are:

* 520 * 510 * 20 * 1

Now I want to create a diff of last three changes, so that I see what has changed from revision 20 until revision 520 INCLUDING these 2 revisions, that means, I want to see all changes that were made in 20, 510 and 520 up to the current version.

I suppose in that case I would set RevID to 520 and DiffTo to 20. That however doesn't seem to work. It shows the diff, but other way, it shows diff from 520 to 20 (and I think it even excludes that revision) not from 20 to 520, including both 20 and 520.

How does the whole thing actually work? I might need something like "DiffFrom" when I think of that, but there is no such a thing. Even more weird thing that happens to me, is that when I swap RevID and DiffTo, the results seem to be identical.