\[the literal [ (9110 / 1338 / 5B16)
\/?optionally matches the literal / (4710 / 578 / 2F16)
Non-Capturing Group(?:b|i|u|sup|url|image|color|size|font){1,} {1,}repeats the group contents below at least once:
bthe literal b (9810 / 1428 / 6216) (case insensitive)
ithe literal i (10510 / 1518 / 6916) (case insensitive)
uthe literal u (11710 / 1658 / 7516) (case insensitive)
supthe literal text sup (case insensitive) urlthe literal text url (case insensitive) imagethe literal text image (case insensitive) colorthe literal text color (case insensitive) sizethe literal text size (case insensitive) fontthe literal text font (case insensitive) .*?any character (except for line terminators), repeated any number of times
]the literal ] (9310 / 1358 / 5D16)
m modifier: multiline. Causes ^ and $ to match the start and end of each line, not only the start and end of the string
g modifier: global. Finds all matches instead of stopping after the first
i modifier: insensitive. Matches without distinguishing uppercase and lowercase letters