Examine source code of IDE Powers

{
  "manifest_version": 2,
  "name": "IDE Powers",
  "description": "Write text like you would in an IDE",
  "version": "0.7.5resigned1",
  "browser_action": {
    "default_popup": "popup.html",
    "default_icon": {
      "16": "img/icon16.png",
      "48": "img/icon48.png"
    },
    "default_title": "IDE Power"
  },
  "icons": {
    "16": "img/icon16.png",
    "48": "img/icon48.png",
    "128": "img/icon128.png",
    "256": "img/icon256.png"
  },
  "permissions": [
    "storage",
    "activeTab"
  ],
  "applications": {
    "gecko": {
      "id": "ff-addon@krister.ee",
      "strict_min_version": "42.0"
    }
  },
  "background": {
    "scripts": [
      "browser.js",
      "background.js"
    ],
    "persistent": false
  },
  "content_scripts": [
    {
      "matches": [
        "<all_urls>"
      ],
      "js": [
        "browser.js",
        "lib/helpers.js",
        "doubleLetters.js",
        "main.js",
        "hotkeys.js"
      ]
    },
    {
      "matches": [
        "*://medium.com/*"
      ],
      "js": [
        "domainSettings/mediumcom.js"
      ]
    },
    {
      "matches": [
        "*://*.facebook.com/*",
        "*://*.messenger.com/*"
      ],
      "js": [
        "domainSettings/facebookcom.js"
      ]
    },
    {
      "matches": [
        "*://*.jsfiddle.net/*"
      ],
      "js": [
        "domainSettings/disabled.js"
      ]
    }
  ],
  "commands": {
    "new-line-above": {
      "suggested_key": {
        "default": "Ctrl+Up"
      },
      "description": "Insert blank line above."
    },
    "new-line-below": {
      "suggested_key": {
        "default": "Ctrl+Down"
      },
      "description": "Insert blank line below."
    },
    "cut-line": {
      "suggested_key": {
        "default": "Ctrl+X"
      },
      "description": "Cut line (delete and keep in clipboard)."
    },
    "delete-line": {
      "suggested_key": {
        "default": "Ctrl+Shift+K"
      },
      "description": "Delete line (just remove it)."
    },
    "move-line-up": {
      "description": "Move line up. (beta & buggy)"
    },
    "move-line-down": {
      "description": "Move line down. (beta & buggy)"
    }
  }
}