* matches the previous token between zero and unlimited times, as many times as possible, giving back as needed (greedy)
\w matches any word character (equivalent to [a-zA-Z0-9_])
0-9 matches a single character in the range between 0 (index 48) and 9 (index 57) (case sensitive)
matches the character -
literally (case sensitive)
This hyphen is treated literally, which might be confusing for others. Consider escaping it or placing at the start or end of the class!
_ matches the character _ literally (case sensitive)