The gcli actor uses some Firefox specific code, like:
let chromeWindow = windowMediator.getMostRecentWindow("navigator:browser");
let contentWindow = chromeWindow.gBrowser.selectedTab.linkedBrowser.contentWindow;
It also uses CommandUtils from resource:///modules/devtools/DeveloperToolbar.jsm, which is in /browser and also uses Firefox-specific code.
We need to figure out how to provide gcli with a sensible content window, especially in cases where the remote end is not Firefox and fix createEnvironment to make the environment's target property more general.
/devtools file move changed everything here...
Triage. Filter on Lobster Thermidor.