Examine source code of Notes Keeper

{
  "name": "Notes Keeper",
  "version": "2.0",
  "manifest_version": 3,
  "description": "An extension to take notes",
  "browser_specific_settings": {
    "gecko": {
      "id": "NotesKeeper@MisterCerberus.org",
      "strict_min_version": "109.0"
    },
    "safari": {
      "id": "NotesKeeper@MisterCerberus.org",
      "strict_min_version": "14.0"
    }
  },
  "icons": {
    "16": "icons/pen16.png",
    "32": "icons/pen32.png",
    "64": "icons/pen64.png",
    "128": "icons/pen128.png"
  },
  "action": {
    "default_popup": "main/index.html"
  },
  "permissions": [
    "downloads"
  ]
}