Examine source code of SignatureSync: Pro Signatures

{
  "manifest_version": 2,
  "browser_specific_settings": {
    "gecko": {
      "id": "{70bd260b-d7d6-4cbb-ba2d-eb18968c33c0}",
      "strict_min_version": "109.0"
    }
  },
  "name": "SignatureSync: Pro Signatures",
  "short_name": "SignatureSync",
  "description": "Simplify your messaging with SignatureSync, the tool that automates your signatures, ensuring a professional touch every time.",
  "version": "4.0.3",
  "icons": {
    "16": "icons/light/icon16.png",
    "32": "icons/light/icon32.png",
    "48": "icons/light/icon48.png",
    "128": "icons/light/icon128.png"
  },
  "browser_action": {
    "default_icon": {
      "16": "icons/light/icon16.png",
      "32": "icons/light/icon32.png",
      "48": "icons/light/icon48.png",
      "128": "icons/light/icon128.png"
    },
    "default_title": "Change/Toggle Signature",
    "default_popup": "popup/index.html"
  },
  "permissions": [
    "storage",
    "*://*.linkedin.com/"
  ],
  "content_scripts": [
    {
      "matches": [
        "*://*.linkedin.com/*"
      ],
      "js": [
        "content.js"
      ]
    }
  ],
  "background": {
    "scripts": [
      "service_worker.js"
    ]
  },
  "web_accessible_resources": [
    "icons/*/icon32.png"
  ]
}