Examine source code of Ampare Max Image Width

{
  "manifest_version": 2,
  "name": "Ampare Max Image Width",
  "version": "1.1resigned1",
  "description": "Making Image Become Max-Width. So It doesn't goes out of border or screen.",
  "homepage_url": "https://www.ampareengine.com",
  "icons": {
    "128": "icon.png"
  },
  "browser_action": {
    "default_icon": "icon.png",
    "browser_style": true
  },
  "permissions": [
    "activeTab",
    "contextMenus",
    "tabs"
  ],
  "background": {
    "scripts": [
      "background.js"
    ]
  },
  "browser_specific_settings": {
    "gecko": {
      "id": "{5ad99ef4-670e-4657-bde5-f5d215f4f455}"
    }
  }
}