Examine source code of ersci_viddown_tab2

{
  "manifest_version": 2,
  "name": "ersci_viddown_tab2",
  "version": "1.4",
  "icons": {
    "48": "icons/icon_48.png"
  },
  "description": "Adds right-click-context-menu which opens currently selected Youtube video link in newtab of your site that opened in browser 2nd tab",
  "background": {
    "scripts": [
      "background.js"
    ]
  },
  "options_ui": {
    "page": "options.html",
    "browser_style": true
  },
  "permissions": [
    "contextMenus",
    "tabs",
    "storage"
  ],
  "browser_specific_settings": {
    "gecko": {
      "id": "epg900@gmail.com_ersci_viddown_tab2"
    }
  }
}