Examine source code of Vision Test

{
  "version": "0.1.5",
  "name": "Vision Test",
  "manifest_version": 3,
  "permissions": [
    "storage"
  ],
  "homepage_url": "https://mybrowseraddon.com/vision-test.html",
  "description": "Test your vision (visual acuity) via Tumbling E chart in your browser!",
  "commands": {
    "_execute_action": {}
  },
  "browser_specific_settings": {
    "gecko": {
      "strict_min_version": "109.0",
      "id": "{e76d4adc-5cc2-4175-93be-601f34687be5}"
    }
  },
  "background": {
    "scripts": [
      "lib/config.js",
      "lib/chrome.js",
      "lib/runtime.js",
      "lib/common.js"
    ]
  },
  "action": {
    "default_title": "Vision Test",
    "default_icon": {
      "16": "data/icons/toolbar/16.png",
      "32": "data/icons/toolbar/32.png",
      "48": "data/icons/toolbar/48.png",
      "64": "data/icons/toolbar/64.png"
    }
  },
  "icons": {
    "16": "data/icons/16.png",
    "32": "data/icons/32.png",
    "48": "data/icons/48.png",
    "64": "data/icons/64.png",
    "128": "data/icons/128.png"
  }
}