Insane arguments always work by abbreviating:

the macro name
one or more of its positional arguments, which are fixed as either literal or non-literal for a given insane construct

This means that you can add further arguments as usual.

For example, an insane code block with an id can be written as:

a `b c`{id=ef} g

because that is the same as:

a \c[b c]{id=ef} g

which renders as:

a
C 1
b c
g

So we see that the b c argument is the very first argument of \c.

Extra arguments must come after the insane opening, e.g. the following does not work:

a {id=ef}`b c` g

This restriction things easy to parse for humans and machines alike.

 Ancestors

Insane macro shortcut extra arguments