Examine source code of LanguageTool Website Spellcheck - LTWS

{
  "manifest_version": 2,
  "name": "LanguageTool Website Spellcheck - LTWS",
  "version": "1.5.1",
  "description": "Check any text on web pages for spelling, grammar, and style issues using the powerful LanguageTool service.",
  "browser_specific_settings": {
    "gecko": {
      "id": "languagetool-contentcheck_MH@example.com"
    }
  },
  "permissions": [
    "contextMenus",
    "http://localhost:8081/*",
    "https://api.languagetool.org/*",
    "storage",
    "activeTab",
    "tabs",
    "<all_urls>"
  ],
  "background": {
    "scripts": [
      "background.js"
    ]
  },
  "content_scripts": [
    {
      "matches": [
        "<all_urls>"
      ],
      "js": [
        "content.js"
      ],
      "css": [
        "spellcheck.css"
      ],
      "run_at": "document_end",
      "all_frames": true
    }
  ],
  "browser_action": {
    "default_title": "LT Website Spellcheck",
    "default_area": "navbar"
  },
  "sidebar_action": {
    "default_title": "LT Website Spellcheck",
    "default_panel": "sidebar.html",
    "default_icon": "icons/48.svg"
  },
  "commands": {
    "_execute_sidebar_action": {
      "suggested_key": {
        "default": "Ctrl+Shift+L"
      },
      "description": "LT Website Spellcheck"
    },
    "check_selected_text": {
      "suggested_key": {
        "default": "Ctrl+Q"
      },
      "description": "Check selected text"
    }
  },
  "icons": {
    "48": "icons/48.svg"
  }
}