IEx v1.12.0

IEx.Helpers.break-exclamation-mark

You're seeing just the function break-exclamation-mark, go back to IEx.Helpers module for more information.
Link to this function

break!(module, function, arity, stops \\ 1)

View Source (since 1.5.0)

Sets up a breakpoint in module, function and arity with the given number of stops.

See IEx.break!/4 for a complete description of breakpoints in IEx.