The ":matches" match type specifies a wildcard match using the characters "*" and "?"; the entire value must be matched. "*" matches zero or more characters in the value and "?" matches a single character in the value, where the comparator that is used (see section 2.7.3) defines what a character is. For example, the comparators "i;octet" and "i;ascii-casemap" define a character to be a single octet, so "?" will always match exactly one octet when one of those comparators is in use. In contrast, a Unicode-based comparator would define a character to be any UTF-8 octet sequence encoding one Unicode character and thus "?" may match more than one octet. "?" and "*" may be escaped as "\\?" and "\\*" in strings to match against themselves. The first backslash escapes the second backslash; together, they escape the "*".