How to use modifier in regular expression (?...) construct

[dangman9]

The documentation says

Modifiers can be embedded within the Regular Expression itself using the (?...) construct.

I'm struggling to figure out what exactly this construct looks like. I'd like to embed case insensitive into an "Included URL" regex. I've tried a few things such as (?i...), (?/i...), (?...)/i, (?.../i) but none of them seem to work. An example would be helpful in the documentation.

[Maksym]

Like this:

(?i)your_reg_ex_here

or this:

(?im)your_reg_ex_here