Examine source code of Opengrapher

{
  "description": "Webextension to use opengrapher on firefox and on chrome",
  "manifest_version": 2,
  "name": "Opengrapher",
  "version": "3.1.3resigned1",
  "homepage_url": "https://github.com/lesspass/webextension",
  "icons": {
    "64": "icons/logo.png"
  },
  "web_accessible_resources": [
    "dist/build.js",
    "dist/build.js.map"
  ],
  "permissions": [
    "activeTab",
    "tabs"
  ],
  "browser_action": {
    "browser_style": false,
    "default_icon": "icons/logo.png",
    "default_title": "Opengrapher",
    "default_popup": "index.html"
  },
  "applications": {
    "gecko": {
      "id": "opengrapher@example.com",
      "strict_min_version": "48.0"
    }
  }
}