In CallFrame§

See primary documentation in context for sub callframe

sub callframe(Int:D $level = 0)

Returns a CallFrame object for the given level. If no level is given, the default level is 0. Positive levels move up the frame stack and negative levels move down (into the call to callframe and deeper).

Returns Mu if there is no call information for the given level. Negative levels may result in an exception.