Examine source code of Achavi button

{
  "manifest_version": 2,
  "name": "Achavi button",
  "version": "0.2.2resigned1",
  "description": "Add button links to Achavi webpage on changesets of the OpenStreetmap web history sidebar",
  "content_scripts": [
    {
      "matches": [
        "*://www.openstreetmap.org/*"
      ],
      "js": [
        "achavi.js"
      ]
    }
  ],
  "browser_specific_settings": {
    "gecko": {
      "id": "{312b204e-8bc3-4fcd-8ae5-abe62f6b35f2}"
    }
  }
}