Examine source code of GitHub Pixel Diff

{
  "manifest_version" : 3 ,
  "name" : "__MSG_extName__" ,
  "version" : "0.18.1",
  "description" : "__MSG_extDescription__" ,
  "default_locale" : "en" ,
  "icons" : {
    "16" : "icons/icon-16.png",
    "32" : "icons/icon-32.png",
    "48" : "icons/icon-48.png",
    "128" : "icons/icon-128.png"
  },
  "permissions" : [
    "storage" ,
    "scripting" 
  ],
  "host_permissions" : [
    "https://viewscreen.githubusercontent.com/*" ,
    "https://gitlab.com/*" 
  ],
  "optional_host_permissions" : [
    "*://*/*" 
  ],
  "content_scripts" : [
    {
      "matches" : [
        "https://viewscreen.githubusercontent.com/diff/img*" 
      ],
      "js" : [
        "vendor/pixelmatch.js" ,
        "shared/locale.js" ,
        "content/i18n.js" ,
        "content/compare.js" ,
        "content/render.js" ,
        "content/worker-host.js" ,
        "content/frame.js" 
      ],
      "css" : [
        "content/panel.css" ,
        "content/frame.css" 
      ],
      "run_at" : "document_end" ,
      "all_frames" : true 
    },
    {
      "matches" : [
        "https://gitlab.com/*" 
      ],
      "js" : [
        "vendor/pixelmatch.js" ,
        "shared/locale.js" ,
        "content/i18n.js" ,
        "content/compare.js" ,
        "content/render.js" ,
        "content/worker-host.js" ,
        "content/gitlab.js" 
      ],
      "css" : [
        "content/panel.css" ,
        "content/gitlab.css" 
      ],
      "run_at" : "document_end" 
    }
  ],
  "web_accessible_resources" : [
    {
      "resources" : [
        "vendor/pixelmatch.js" ,
        "content/compare.js" ,
        "content/worker.js" 
      ],
      "matches" : [
        "*://*/*" 
      ],
      "use_dynamic_url" : true 
    }
  ],
  "action" : {
    "default_title" : "__MSG_extName__" ,
    "default_popup" : "popup/popup.html",
    "default_icon" : {
      "16" : "icons/icon-16.png",
      "32" : "icons/icon-32.png"
    }
  },
  "options_ui" : {
    "page": "options/options.html" ,
    "open_in_tab": true
  },
  "browser_specific_settings": {
    "gecko": {
      "id": "gh-pixel-diff@nemo-illusionist.github.io",
      "strict_min_version": "128.0",
      "data_collection_permissions": {
        "required": [
          "none"
        ]
      }
    },
    "gecko_android": {
      "strict_min_version": "128.0"
    }
  }
}