Overriding the URL for new tabs in Firefox, updated

[djinncoyote]

As of Firefox version 59, the syntax listed in my prior post no longer works for overriding the new tab URL.

The "local-settings.js" file can remain the same as before.

But the "mozilla.cfg" file instead needs syntax like this now:

var {classes:Cc, interfaces:Ci, utils:Cu} = Components;

try {
   var newTabURL = "file:///C:/path/to/html/file.htm";
   aboutNewTabService = Cc["@mozilla.org/browser/aboutnewtab-service;1"].getService(Ci.nsIAboutNewTabService);
   aboutNewTabService.newTabURL = newTabURL;
   pref("browser.newtab.url", aboutNewTabService.newTabURL);
} catch(e) {
   Cu.reportError(e);
}

The above info was posted by user "cor-el" on this page:
https://support.mozilla.org/eu/questions/1202974