The help page ?type/protected states:

The set of protected names in Maple can be computed with select(type, {unames(), anames(anything)}, protected).

However, the result of this computation is "time dependent". I.e. repeated execution of this command produce different sets. E.g. executed in a fresh session:

The calling sequence in ?complex states only the two argument form 'Complex(x, y)', but later in the section "Description", in a bit confusing way, two rules for the single argument form are stated:

As the discussion in this thread  did not provide me a clear understanding of the implementation and intended usage of the property 'continuous' I have looked at this subject a bit further. And as it is an underdocumented subject, it seems fit to post here some issues that I have found.

Because of John's answer to my last comment about a Maple wiki, I have searched first for antecedents in Maple Primes. From the many posts found in this search, I put together here what I consider the main points stated so far.

Oficial plans + technology:

http://www.mapleprimes.com/forum/how_do_we_grow_this_site