"I'd call a trick something that is not part of the documentation core .." I'd call this particular definition a pedantic, artificial nitpick invented soley for the purpose of picking nits in the post.
If on the other hand you use a conventional definition of trick, "a clever or particular way of doing something", then the post is indeed about a set of tricks.
If on the other hand you use a conventional definition of trick, "a clever or particular way of doing something", then the post is indeed about a set of tricks.