Examine source code of Thicctodon

{
  "manifest_version": 2,
  "name": "Thicctodon",
  "version": "1.0",
  "description": "Change your Mastodon's columns size",
  "icons": {
    "16": "icons/Thicctodon-16.png",
    "48": "icons/Thicctodon-48.png",
    "128": "icons/Thicctodon-128.png"
  },
  "permissions": [
    "activeTab"
  ],
  "browser_action": {
    "default_icon": "icons/Thicctodon-48.png",
    "default_title": "Thicctodon",
    "default_popup": "popup/config.html"
  },
  "browser_specific_settings": {
    "gecko": {
      "id": "{cec276a9-20a1-4153-a8dc-39127f9cbd51}"
    }
  }
}