layout 中 environment 标记的用处

Question

<environment include="Development"><link rel="stylesheet" href="~/lib/bootstrap/dist/css/bootstrap.css" /><link rel="stylesheet" href="~/css/site.css" /></environment><environment exclude="Development"><link rel="stylesheet" href="https://ajax.aspnetcdn.com/ajax/bootstrap/3.3.7/css/bootstrap.min.css"asp-fallback-href="~/lib/bootstrap/dist/css/bootstrap.min.css"asp-fallback-test-class="sr-only" asp-fallback-test-property="position" asp-fallback-test-value="absolute" /><link rel="stylesheet" href="~/css/site.min.css" asp-append-version="true" /></environment>.Net Core 2.0 _layout.cshtml 文件中有这些样式表及JS的引用，请教哪里有这些标记详细的说明文档？