any
  OR  (as an element test)
  content is any

Can be used in a pattern to match all possible characters or can be used in an element content-type test.

When used in pattern matching, any can be used with any of the pattern repetition and optionality modifiers:

• any+ -- any character must occur at least once, and may occur several times
• any* -- any character can occur several times, or not at all
• any? -- any character may occur once, or may be omitted

any may be used as part of a custom character class to precisely define the characters sought. For example, to define a character class consisting of non-ASCII vowels, the class can be defined as: [any except "aeiouAEIOU"].

As an element test, any is used specifically in a content is test. Briefly, the test succeeds if the stated element is declared of type any.