Examine source code of Textarea Cache M

{
  "applications": {
    "gecko": {
      "id": "textarea-cache-lite.M@gholk.github.io",
      "strict_min_version": "58.0"
    }
  },
  "manifest_version": 2,
  "name": "Textarea Cache M",
  "version": "4.8.0",
  "default_locale": "en",
  "description": "Allows to save automatically the content in a text input field.",
  "homepage_url": "https://github.com/GHolk/TextareaCache/tree/tcm",
  "icons": {
    "48": "icons/icon.png"
  },
  "permissions": [
    "storage",
    "clipboardWrite",
    "menus",
    "alarms"
  ],
  "browser_action": {
    "browser_style": true,
    "default_title": "View your saved data (Textarea Cache)",
    "default_icon": "icons/tacache-48.png"
  },
  "page_action": {
    "browser_style": true,
    "default_title": "View your saved data (Textarea Cache)",
    "default_icon": "icons/tacache-48-bw.png"
  },
  "content_scripts": [
    {
      "match_about_blank": true,
      "all_frames": true,
      "matches": [
        "<all_urls>"
      ],
      "run_at": "document_idle",
      "js": [
        "browser-polyfill.min.js",
        "content-script.js"
      ]
    }
  ],
  "background": {
    "scripts": [
      "browser-polyfill.min.js",
      "common.js",
      "ta_database.js",
      "ta_bg.js",
      "background.js"
    ]
  },
  "options_ui": {
    "browser_style": true,
    "page": "options/options.html"
  }
}