Examine source code of Calm Echo Panel

{
  "manifest_version": 2,
  "name": "Calm Echo Panel",
  "version": "1.0.0",
  "description": "A clean static echo panel that displays local offline content without permissions.",
  "permissions": [],
  "icons": {
    "48": "icons/48.png",
    "96": "icons/96.png"
  },
  "browser_action": {
    "default_title": "Calm Echo Panel",
    "default_popup": "popup.html",
    "default_icon": {
      "48": "icons/48.png",
      "96": "icons/96.png"
    }
  },
  "browser_specific_settings": {
    "gecko": {
      "id": "calm-echo-panel@example.com",
      "strict_min_version": "58.0",
      "data_collection_permissions": {
        "required": [
          "none"
        ]
      }
    }
  },
  "data_collection_permissions": [],
  "data_collection": {
    "collects_data": false
  }
}