Examine source code of ReloadTabByMidClick

{
  "name": "Reload Tab by Double Middle Click",
  "version": "0.4",
  "manifest_version": 2,
  "description": "Reload tab by double middle clicking anywhere on the page.",
  "icons": {
    "48": "icon.svg",
    "96": "icon.svg"
  },
  "permissions": [
    "<all_urls>",
    "contextMenus",
    "tabs"
  ],
  "background": {
    "page": "background.html"
  },
  "browser_specific_settings": {
    "gecko": {
      "id": "{295cc6f7-27f6-441f-b70c-28fbd46ff751}"
    }
  }
}