manifest.json

{
  "name": "Fresh Chrome Extension",
  "description": "Fully functional, useful bare minimum Google Chrome extension boilerplate [Manifest V3].",
  "homepage_url": "https://github.com/llagerlof/fresh-chrome-extension",
  "version": "2.0.0",
  "manifest_version": 3,
  "action": {
    "default_title": "execute.js will run (watch the Chrome DevTools' console)"
  },
  "content_scripts": [
    {
      "run_at" : "document_start",
      "js": ["before.js"],
      "matches": [
        "https://*/*",
        "http://*/*"
      ]
    },
    {
      "run_at" : "document_idle",
      "js": ["after.js"],
      "matches": [
        "https://*/*",
        "http://*/*"
      ]
    }
  ],
  "background": {
    "service_worker": "background.js"
  },
  "permissions": [
    "tabs",
    "scripting"
  ],
  "host_permissions": [
    "https://*/*",
    "http://*/*"
  ]
}