Here is at least a correction of Descriptors' HowTo. There are two versions since some stuff differs (object inheritance, ...).

Here are some of my interrogations though:
 - RevealAccess is not using instance parameter, so value is shared. Is this intended?
 - Don't really know what to do with "Function and Methods" part. First I don't really understand the relevance of this in a descriptor how-to. Also it is know outdated in python3 version (unbound thing, ...), so what do?
 - In __getattribute__ function, I don't really understand the paramters given to __get__, why None and the instance? But this is probably my fault.

This also doesn't answer the question about the real source that should be kept. What to do?

I also need a proof-read, since english is not my first language... Anyway it's clearly not enough to be published like that

Have a nice day!