^

Indicates the beginning of a string.

^ (notwithstanding) matches any block of text that began with "notwithstanding" So the phrase "notwithstanding the fact that I like vegetables in my soup" would trigger the regex, but "The fact that I like vegetables in my soup notwithstanding" would not.

$

Indicates the end of a string.

(notwithstanding) $ matches any block of text that ended with "notwithstanding" So the phrase "notwithstanding the fact that I like vegetables in my soup" would not trigger the regex, but "The fact that I like vegetables in my soup notwithstanding" would.