(?smi)applies the following effective flags to the remainder of the pattern: msi s modifier: single line. Allows a dot to match line terminators
m modifier: multiline. Causes ^ and $ to match the start and end of each line, not only the start and end of the string
i modifier: insensitive. Matches without distinguishing uppercase and lowercase letters
^start of line
.*any character, repeated any number of times
tag="the literal text tag=" (case insensitive) A-Zone character from A (6510) to Z (9010) (case insensitive)
_the literal _ (9510 / 1378 / 5F16)
{2}matches exactly 2 characters from the set below:
A-Zone character from A (6510) to Z (9010) (case insensitive)
_the literal _ (9510 / 1378 / 5F16)
\d{4}a digit, repeated exactly 4 times
.*any character, repeated any number of times
$end of line
m modifier: multiline. Causes ^ and $ to match the start and end of each line, not only the start and end of the string
s modifier: single line. Allows a dot to match line terminators
i modifier: insensitive. Matches without distinguishing uppercase and lowercase letters