Examine source code of Activate Reader View

{
  "description": "__MSG_extensionDescription__",
  "manifest_version": 2,
  "name": "__MSG_extensionName__",
  "short_name": "__MSG_extensionShortName__",
  "version": "0.1.2",
  "developer": {
    "name": "Florian Kohrt"
  },
  "default_locale": "en",
  "applications": {
    "gecko": {
      "id": "@activatereaderview",
      "strict_min_version": "58.0a1"
    }
  },
  "icons": {
    "48": "icons/readerModeGrayWhite-48.png",
    "96": "icons/readerModeGrayWhite-96.png"
  },
  "permissions": [
    "tabs"
  ],
  "background": {
    "scripts": [
      "activatereaderview.js"
    ]
  },
  "browser_action": {
    "default_icon": "icons/readerModeGrayWhite-32.png",
    "default_title": "__MSG_browserActionTitle__"
  }
}