Examine source code of Spotlight

{
  "manifest_version": 2,
  "name": "Spotlight",
  "description": "Spotlight page elements for clean screenshots",
  "version": "0.2.0",
  "icons": {
    "16": "icon/16.png",
    "32": "icon/32.png",
    "48": "icon/48.png",
    "128": "icon/128.png"
  },
  "permissions": [
    "activeTab",
    "storage",
    "downloads",
    "<all_urls>"
  ],
  "commands": {
    "toggle_selection": {
      "suggested_key": {
        "default": "Alt+Shift+S"
      },
      "description": "Toggle selection mode"
    }
  },
  "browser_specific_settings": {
    "gecko": {
      "id": "spotlight@tryspotlight.app",
      "data_collection_permissions": {
        "required": [
          "none"
        ]
      }
    }
  },
  "background": {
    "scripts": [
      "background.js"
    ]
  },
  "content_scripts": [
    {
      "matches": [
        "<all_urls>"
      ],
      "run_at": "document_idle",
      "js": [
        "content-scripts/content.js"
      ]
    }
  ],
  "browser_action": {
    "default_title": "Spotlight"
  }
}