Examine source code of Frizzle App: Fashion brand as an app

{
  "manifest_version": 2,
  "name": "Frizzle App",
  "version": "1.0.1911.3",

  "description": "Frizzle App Firefox Add-on",

  "short_name": "Frizzle App",

  "developer": {
    "name": "Frizzle Apps",
    "url": "https://www.whatsitwhatsit.com/about/"
  },

  // "Even though you can use one file, you still need to specify various size of the icon in your manifest." 
  // Oh, even if svg is used...
  "icons": {
    "48": "icons/Icon_anim_on_generator_page.png",
    "64": "icons/Icon_anim_on_generator_page.png",
    "96": "icons/Icon_anim_on_generator_page.png"

  },
  "applications": {
    "gecko": {
      "id": "frizzleapp-firefox@frizzleapps.com",
      "strict_min_version": "65.0"
    }
  },
  "permissions": [
    "activeTab",
    "tabs",
    "downloads",
    "<all_urls>",
    "contextMenus",
    "notifications",
    "storage"
  ],  
  "commands": {
    "toggle-feature": {
      "suggested_key": {
        "default": "F9"
      },
      "description": "Send a 'toggle-feature' event"
    }
  },
  "background": {
    "scripts": ["background.js"]
  },
  "content_scripts": [
    {
      "matches": ["*://www.frizzleapps.com/content/*", "*://test.frizzleapps.com/content/*"],
      "js": ["detect_extension_installed.js"],
      "run_at": "document_idle"
    },
    {
      "matches": ["<all_urls>"],
      "js": ["on_catalog_page.js"],
      "run_at": "document_end",
      "match_about_blank": true
    }
  ], 
  "browser_action": {
    "default_popup": "popup/index.html",
    "default_icon": "icons/Icon_gray.png"
  }
}