Examine source code of Change Image Background

{
  "manifest_version": 3,
  "version": "1.0.0",
  "name": "Change Image Background",
  "description": "Replace photo background with other image or image filters",
  "action": {
    "default_title": "Change Image Background",
    "default_icon": {
      "16": "16.png",
      "32": "32.png",
      "48": "48.png",
      "128": "128.png"
    }
  },
  "background": {
    "scripts": [
      "background.js"
    ]
  },
  "browser_specific_settings": {
    "gecko": {
      "id": "appeffectchangeimagebg@gmail.com"
    }
  },
  "icons": {
    "16": "16.png",
    "32": "32.png",
    "48": "48.png",
    "128": "128.png"
  },
  "permissions": [],
  "web_accessible_resources": [
    {
      "matches": [],
      "resources": [
        "index.html"
      ]
    }
  ]
}