This is a Database Documentation idea. There may be a more appropriate place to post it, but I couldn't find one.
When having to deal with an unfamiliar bit of functionality, my first resort is to Google for what I'm dealing with, eg: "Oracle Subpartition". If you do that search, you'll get this page #2 in the results:
It's an Oracle page. It's about subpartitions, The only problem is that it's about MySQL. That particular page does mention in passing that it's from a MySQL manual (not all of them do), but it's not exactly obvious. Could Oracle not add a prominent banner to the top of their MySQL manual pages saying that they are MySQL manual pages?