<imgthe literal text <img (case insensitive) .*?any character (except for line terminators), repeated any number of times
srcthe literal text src (case insensitive) \s*any whitespace character, repeated any number of times
=the literal = (6110 / 758 / 3D16)
\s*any whitespace character, repeated any number of times
"the literal " (3410 / 428 / 2216)
Group 1([^"]*\?contextId[^"]*) Negated Character Class[^"]* *matches any number of characters outside the set below:
"the literal " (3410 / 428 / 2216)
\?the literal ? (6310 / 778 / 3F16)
contextIdthe literal text contextId (case insensitive) Negated Character Class[^"]* *matches any number of characters outside the set below:
"the literal " (3410 / 428 / 2216)
g modifier: global. Finds all matches instead of stopping after the first
i modifier: insensitive. Matches without distinguishing uppercase and lowercase letters