Examine source code of ColorBeta

{
  "action": {
    "default_icon": {
      "16": "img/16.png",
      "32": "img/32.png"
    },
    "default_title": "__MSG_default_title__",
    "default_popup": "html/popup.html"
  },
  "manifest_version": 3,
  "name": "__MSG_name__",
  "version": "1.0.1",
  "default_locale": "en",
  "description": "__MSG_description__",
  "icons": {
    "16": "img/16.png",
    "32": "img/32.png",
    "48": "img/48.png",
    "96": "img/96.png",
    "128": "img/128.png"
  },
  "browser_specific_settings": {
    "gecko": {
      "id": "addon@colorbeta.com",
      "strict_min_version": "120.0"
    }
  }
}