2.2.3.20 Wildcard
This data type represents a wildcard pattern that can be matched against a String (see section 2.2.5.1.1).
This data type is a String (see section 2.2.5.1.1) with the contents interpreted according to IEEE Std 1003.1, 2004 Edition section 2.13.2 "Patterns Matching Multiple Characters [IEEE1003.1-chap2] with the following exceptions:
The backtick character ("`") is used as an escape character, instead of a backslash character ("\").
The exclamation character ("!") in a bracket expression does not have a special meaning.
All character comparisons are locale-invariant, ordinal-based, and case-insensitive, as defined in [MS-UCODEREF] section 3.1.5.5.