https://learn.microsoft.com/ja-jp/dotnet/api/system.web.ui.scriptmanager.scriptmode?view=netframework-4.8.1&redirectedfrom=MSDN
ScriptManager.ScriptMode Property (System.Web.UI) | Microsoft Learn
Gets or sets a value that specifies whether debug or release versions of client script libraries are rendered.
property systemweb uimicrosoftlearn