Liberator.Resource.handle_error

You're seeing just the callback handle_error, go back to Liberator.Resource module for more information.
Link to this callback

handle_error(arg1, term, atom)

View Source (since 1.3)

Specs

handle_error(Plug.Conn.t(), term(), atom()) :: Plug.Conn.t()

Returns a conn for a 500 Internal Server Error response.

This handler is special among the handlers. Not only does it receive the conn, it also receives the error that was thrown, as well as the atom name of the failed step.