Examine source code of Session Sync

{
  "manifest_version": 3,
  "name": "Session Sync",
  "description": "Save sessions as bookmarks and sync them through Firefox Sync (or any other sync engine).\nPowerful session management - organize, edit, change, save, restore, etc\n",
  "version": "3.3.1",
  "icons": {
    "16": "images/icon16.png",
    "32": "images/icon32.png",
    "48": "images/icon48.png",
    "64": "images/icon64.png",
    "96": "images/icon96.png",
    "128": "images/icon128.png"
  },
  "author": "Gabriel Ivanica",
  "homepage_url": "https://github.com/ReDEnergy/SessionSync",
  "default_locale": "en",
  "browser_specific_settings": {
    "gecko": {
      "id": "session-sync@gabrielivanica.com",
      "data_collection_permissions": {
        "required": [
          "none"
        ]
      }
    }
  },
  "permissions": [
    "storage",
    "bookmarks",
    "tabs",
    "clipboardWrite",
    "unlimitedStorage",
    "cookies",
    "contextualIdentities",
    "tabGroups"
  ],
  "action": {
    "default_icon": {
      "16": "images/icon16.png",
      "32": "images/icon32.png",
      "48": "images/icon48.png",
      "128": "images/icon128.png"
    },
    "default_title": "Session Sync",
    "default_popup": "session-sync.html"
  },
  "commands": {
    "_execute_action": {
      "suggested_key": {
        "default": "Ctrl+Shift+F"
      },
      "description": "Widget View"
    },
    "session_sync_detach_tab": {
      "suggested_key": {
        "default": "Ctrl+Shift+U"
      },
      "description": "Tab View"
    },
    "session_sync_detach_window": {
      "suggested_key": {
        "default": "Ctrl+Shift+F6"
      },
      "description": "Window View"
    }
  },
  "background": {
    "scripts": [
      "background.js"
    ]
  }
}