Checks a string for whether it contains only word characters. This is logically equivalent to the \w PCRE meta character. Note that this is not a 100% guarantee that the string only contains alpha / numeric characters but just that common non-alphanumeric are not in the string, including ASCII device control characters.
Located at vendor/joomla/string/src/phputf8/utils/specials.php
Return value summary
||TRUE if the string only contains word characters|