Examine source code of Brickseek

{
  "name": "Brickseek",
  "version": "1.0.1",
  "manifest_version": 2,
  "description": "Adds 'Open in Brickseek' button to Walmart product pages",
  "homepage_url": "https://github.com/andrew-ma/brickseek",
  "minimum_chrome_version": "74",
  "browser_specific_settings": {
    "gecko": {
      "id": "brickseek@andrewmatech.com",
      "strict_min_version": "67.0"
    }
  },
  "icons": {
    "48": "/icon.png",
    "96": "/icon@2x.png"
  },
  "content_scripts": [
    {
      "all_frames": true,
      "matches": [
        "*://www.walmart.com/ip/*"
      ],
      "js": [
        "/brickseek.js"
      ],
      "css": [
        "/brickseek.css"
      ]
    }
  ]
}