Add to OmniFocus for Gmail

manifest.json

{
  "update_url": "https://clients2.google.com/service/update2/crx",
  "manifest_version": 3,
  "name": "Add to OmniFocus for Gmail",
  "short_name": "OmniFocus",
  "version": "1.3.0",
  "description": "Adds a button to Gmail threads to add them to OmniFocus, including a link to the message.",
  "content_scripts": [
    {
      "matches": [
        "https://mail.google.com/*"
      ],
      "js": [
        "dist/index.js"
      ]
    }
  ],
  "icons": {
    "128": "resources/icon.png"
  },
  "web_accessible_resources": [
    {
      "resources": [
        "dist/index.js",
        "resources/**"
      ],
      "matches": [
        "*://*/*"
      ]
    }
  ]
}