Grimacing to Pain Peko Smiling

manifest.json

{
  "update_url": "https://clients2.google.com/service/update2/crx",
  "name": "Grimacing to Pain Peko Smiling",
  "short_name": "Pain Peko Smiling",
  "manifest_version": 3,
  "version": "1.0",
  "description": "Replaces all grimaces with pain peko smiles.",
  "author": "Reto Fever",
  "icons": {
    "16": "images/pain-peko-16.png",
    "32": "images/pain-peko-32.png",
    "48": "images/pain-peko-48.png",
    "128": "images/pain-peko-128.png"
  },
  "content_scripts": [
    {
      "matches": [
        "*://*/*"
      ],
      "all_frames": true,
      "js": [
        "scripts/content_script.js"
      ],
      "run_at": "document_end"
    }
  ]
}