Examine source code of Mirror or move Page

{
  "manifest_version": 2,
  "name": "Mirror Page, Keep Text",
  "version": "1.0.0",
  "description": "Mirrors and shifts the current page horizontally while keeping visible text readable.",
  "icons": {
    "16": "mirror-view-16-svgrepo-com.svg",
    "32": "mirror-view-16-svgrepo-com.svg",
    "48": "mirror-view-16-svgrepo-com.svg",
    "96": "mirror-view-16-svgrepo-com.svg",
    "128": "mirror-view-16-svgrepo-com.svg"
  },
  "permissions": [
    "<all_urls>",
    "tabs"
  ],
  "browser_action": {
    "default_icon": {
      "16": "mirror-view-16-svgrepo-com.svg",
      "32": "mirror-view-16-svgrepo-com.svg"
    },
    "default_title": "Mirror page controls",
    "default_popup": "popup.html"
  },
  "background": {
    "scripts": [
      "background.js"
    ]
  },
  "content_scripts": [
    {
      "matches": [
        "<all_urls>"
      ],
      "js": [
        "content.js"
      ],
      "run_at": "document_idle",
      "all_frames": true
    }
  ],
  "browser_specific_settings": {
    "gecko": {
      "id": "mirror-page-keep-text@example.local",
      "data_collection_permissions": {
        "required": [
          "none"
        ],
        "optional": []
      }
    }
  }
}