Examine source code of kWh-GRS

{
  "id": "kwh-grs",
  "applications": {
    "gecko": {
      "id": "groestlcoin@gmail.com",
      "strict_min_version": "57.0"
    }
  },
  "manifest_version": 2,
  "name": "kWh-GRS",
  "description": "Send and receive Groestlcoin Lightning payments in the browser with c-lightning, Groestlcoin Eclair or Ptarmigan.",
  "version": "0.5.3.2",
  "author": "groestlcoin developers",
  "icons": {
    "16": "icon16.png",
    "48": "icon48.png",
    "64": "icon64.png",
    "128": "icon128.png"
  },
  "options_ui": {
    "page": "options.html",
    "browser_style": true,
    "open_in_tab": false
  },
  "content_scripts": [
    {
      "matches": [
        "file://*/*",
        "http://*/*",
        "https://*/*"
      ],
      "js": [
        "content-bundle.js"
      ],
      "run_at": "document_start",
      "all_frames": true
    }
  ],
  "background": {
    "scripts": [
      "background-bundle.js"
    ],
    "persistent": true
  },
  "browser_action": {
    "default_icon": {
      "16": "icon16.png",
      "64": "icon64.png"
    },
    "default_title": "KwH-GRS",
    "default_popup": "popup.html"
  },
  "web_accessible_resources": [
    "webln-bundle.js"
  ],
  "permissions": [
    "storage",
    "clipboardWrite",
    "notifications",
    "contextMenus",
    "tabs",
    "<all_urls>"
  ]
}