manifest.json

{
   "manifest_version": 2,
    "name": "DEMO WebExtension Manifest",
    "version": "1.5",
    "description": "Demo WebExtension Manifest for the WebExtensions of the browser",
    "icons": {
        "48":  "icons/icon-48.png",
        "32":  "icons/icon-32.png",
        "96":  "icons/icon-96.png",
        "16":  "icons/icon-16.png"
    },
    
    "browser_action": {
        "default_title": "DEMO WebExtension Manifest",
        "default_icon":  "icons/icon-128.png",
        "default_popup": "browser_action/popup.html"
    },
    

    "content_scripts": [
      {
        "matches": ["*://www.mozilla.org/*","*://localhost/*"],
        "js": ["background/mozilla.js"]
      }, 
      {
        "matches": ["<all_urls>"],
        "exclude_matches": ["*://www.mozilla.org/*"],
        "js": ["background/all-sites.js"]
      }
    ],
    "web_accessible_resources": [
        "resources/*"
    ],
    "permissions": [
        "<all_urls>",
        "notifications",
        "tabs"
    ]
}