Negative Lookahead(?!(?1)) (?1)calls group 1 as a subroutine
\Q\1?!($!?)?\Ethe literal text \1?!($!?)?
\1?optionally matches the text saved by group 1
!the literal ! (3310 / 418 / 2116)
?repeats the group contents below at most once:
$end of string, or before its final line terminator
!?optionally matches the literal ! (3310 / 418 / 2116)
Negative Lookbehind(?<!.{12}) .{12}any character (except for line terminators), repeated exactly 12 times
\Q(?=(?1))\Ethe literal text (?=(?1))
Positive Lookahead(?=(?1)) (?1)calls group 1 as a subroutine
!the literal ! (3310 / 418 / 2116)
\?the literal ? (6310 / 778 / 3F16)
$end of string, or before its final line terminator