The REGEX object is a set of key/value pairs, where some of the values are strings and some of them functions. WORD_CHARACTER or WORD \w Find any word character, equivalent to [a-zA-Z_0-9] ...

Another quantifier for this regex includes {2,6}, which will allow a match range of 2-6 characters for the character set of [a-z.]. Capturing group #1 in this expression is ([a-z0-9_.-]+) that matches ...