There are multiple things that can simply not be done in a UI of
creating panels and sidebars. To allow these things to be done,
epack has the option for you to create a custom DevTools Script
that will be run whenever the Chrome DevTools opens. It gives
access to most of the chrome.devtools API. To create a DevTool
Script, press the create button as normal, but instead of creating
a new panel, create a DevTools Script. This will give you a prompt
asking the name and the number of scripts. You can choose to run
multiple pieces of code in one time by increasing the number.
After you click create, a new panel will be created allowing you
to change around the scripts.