Examine source code of Focus Mode Lite

{
  "manifest_version": 2,
  "name": "Focus Mode",
  "version": "1.0",
  "description": "Hide everything except main article text",
  "permissions": [
    "activeTab"
  ],
  "browser_specific_settings": {
    "gecko": {
      "id": "{887736d3-4a0e-4d17-a3f8-add6e5807eb2}",
      "strict_min_version": "114.0"
    }
  },
  "icons": {
    "64": "icon64.png",
    "128": "icon128.png"
  },
  "browser_action": {
    "default_title": "Focus Mode",
    "default_popup": "popup.html"
  }
}