What does (?: do in a regular expression

Question

I have come across a regular expression that I don\'t fully understand - can somebody help me in deciphering it:

^home(?:\\/|\\/index\\.asp)?(?:\\?.+)?$
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Answer 1

From documentation:

(?:...)
A non-capturing version of regular parentheses. Matches whatever regular expression is inside the parentheses, but the substring matched by the group cannot be retrieved after performing a match or referenced later in the pattern.