Examine source code of TaskColors

{
  "manifest_version": 3,
  "name": "TaskColors",
  "version": "1.0",
  "description": "Adds a color picker to Google Calendar tasks.",
  "permissions": [
    "storage",
    "scripting"
  ],
  "host_permissions": [
    "https://calendar.google.com/*"
  ],
  "content_scripts": [
    {
      "matches": [
        "https://calendar.google.com/*"
      ],
      "js": [
        "content.js"
      ],
      "css": [
        "styles.css"
      ]
    }
  ],
  "action": {
    "default_icon": "icon2.png"
  },
  "browser_specific_settings": {
    "gecko": {
      "id": "taskcolors@wilson.dev"
    }
  }
}