XSLT 2.0 and XPath 2.0 Programmer's Reference, 4th Edition (471 page)

TextTest	text ( )
PITest	processing-instruction ( (NCName | StringLiteral)? )

If you're reading the book sequentially, you may have a sense of
déjà vu
about these rules. We met them before in Chapter 9, on page 616, where they appear as part of the syntax for a
NodeTest
in a path expression. Conveniently, the syntax for testing the type of a node in an
instance
of
or
treat as
expression is exactly the same as the syntax for saying what kinds of node you want to select in a step of a path expression. What's more, because the syntax of XSLT match patterns is defined in terms of path expressions, you can use the same constructs when defining an XSLT template rule.