UserAgent: Mozilla/5.0 (Macintosh; Intel Mac OS X 10_11_6) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/57.0.2986.0 Safari/537.36

Steps to reproduce the problem:
Imagine a textbox that lets you add a regex URL pattern, with a list of options on how to respond to requests when the pattern is matched (e.g. return 500, or canned data)

What is the expected behavior?

What went wrong?
Not implemented.

Did this work before? No 

Chrome version: 57.0.2986.0  Channel: dev
OS Version: OS X 10.11.6
Flash Version: 

This is a community request: https://twitter.com/deathbypapercut/status/821810781775872001