Examine source code of Tab Replacer

{
  "manifest_version": 2,
  "name": "Tab Replacer",
  "version": "3.0",
  "description": "Replace current tab with any URL using Alt+Y or popup",
  "permissions": [
    "tabs"
  ],
  "browser_action": {
    "default_popup": "popup.html",
    "default_title": "Tab Replacer"
  },
  "commands": {
    "activate-tab-replacer": {
      "suggested_key": {
        "default": "Alt+Y"
      },
      "description": "Open Tab Replacer popup"
    }
  },
  "browser_specific_settings": {
    "gecko": {
      "id": "{a1aeffcb-1866-45b9-903b-c9ce3df41fc1}"
    }
  }
}