Examine source code of PerfectPixel by WellDoneCode (pixel perfect)

{
  "background" : {
    "scripts" : [
      "background.js" 
    ]
  },
  "browser_specific_settings": {
    "gecko": {
      "id": "{4c47d1b1-c33d-4b05-908f-90c05bf6e2ab}",
      "strict_min_version": "147.0",
      "data_collection_permissions": {
        "required": [
          "none"
        ],
        "optional": [
          "technicalAndInteraction",
          "authenticationInfo"
        ]
      }
    }
  },
  "action" : {
    "default_icon" : "assets/images/icons/app_icons/disabled.png",
    "default_title" : "PerfectPixel"
  },
  "sidebar_action": {
    "default_panel": "sidepanel.html",
    "default_title" : "PerfectPixel",
    "default_icon" : "assets/images/icons/app_icons/default.png",
    "open_at_install": false
  },
  "commands" : {
    "_execute_sidebar_action": {
      "suggested_key": {
        "default": "Alt+Shift+P"
      }
    }
  },
  "content_security_policy" : {
    "extension_pages": "script-src 'self'; object-src 'self'"
  },
  "default_locale" : "en" ,
  "description" : "__MSG_extension_description__" ,
  "icons" : {
    "16" : "assets/images/icons/16.png",
    "48" : "assets/images/icons/48.png",
    "128" : "assets/images/icons/128.png"
  },
  "name" : "__MSG_extension_name__" ,
  "manifest_version" : 3 ,
  "options_ui" : {
    "page": "settings.html" ,
    "open_in_tab": true
  },
  "optional_permissions" : [
    "clipboardRead" 
  ],
  "permissions" : [
    "activeTab" ,
    "scripting" ,
    "storage" ,
    "unlimitedStorage" 
  ],
  "host_permissions" : [
    "<all_urls>" 
  ],
  "short_name" : "PerfectPixel",
  "version" : "3.2.0.8",
  "web_accessible_resources" : [
    {
      "resources" : [
        "assets/**" ,
        "styles/**" 
      ],
      "matches" : [
        "<all_urls>" 
      ]
    }
  ]
}