Examine source code of Tab Deque

{
  "applications": {
    "gecko": {
      "id": "tabdeque@sblask",
      "strict_min_version": "57.0"
    }
  },
  "author": "Sebastian Blask",
  "background": {
    "scripts": [
      "background.js"
    ]
  },
  "commands": {
    "select-tab-from-end-of-tabdeque": {
      "description": "Select tab from end of TabDeque",
      "suggested_key": {
        "default": "Ctrl+Up"
      }
    },
    "send-tab-to-end-of-tabdeque": {
      "description": "Send tab to end of TabDeque",
      "suggested_key": {
        "default": "Ctrl+Down"
      }
    }
  },
  "description": "A webextension for better tab handling. Inspired by Opera 12.",
  "homepage_url": "https://github.com/sblask/webextension-tab-deque",
  "icons": {
    "48": "icon.svg"
  },
  "manifest_version": 2,
  "name": "Tab Deque",
  "options_ui": {
    "page": "options/options.html"
  },
  "permissions": [
    "contextMenus",
    "storage"
  ],
  "version": "2.1.1resigned1"
}