Azure门户是否使用未公开的ARM功能来部署App Services？

Question

我正在查看为添加由Azure门户生成的Web应用而生成的模板。我选择.NET core作为运行时，并将其传递给下面生成的ARM模板中的metadata字段，其值为dotnetcore。最终结果是在Azure中创建的资源具有您期望从Web应用程序获得的所有内容。我没有看到该字段的文档，也没有解释如何使用它。是一些内部专有技术或此过程如何运作？

 "resources": [
        {
            "apiVersion": "2018-11-01",
            "name": "[parameters('name')]",
            "type": "Microsoft.Web/sites",
            "location": "[parameters('location')]",
            "tags": {},
            "dependsOn": [],
            "properties": {
                "name": "[parameters('name')]",
                "siteConfig": {
                    "appSettings": [
                        {
                            "name": "ANCM_ADDITIONAL_ERROR_PAGE_LINK",
                            "value": "[parameters('errorLink')]"
                        }
                    ],
                    "metadata": [
                        {
                            "name": "CURRENT_STACK",
                            "value": "[parameters('currentStack')]"
                        }
                    ],
                    "phpVersion": "[parameters('phpVersion')]",
                    "alwaysOn": "[parameters('alwaysOn')]"
                },
                "serverFarmId": "[concat('/subscriptions/', parameters('subscriptionId'),'/resourcegroups/', parameters('serverFarmResourceGroup'), '/providers/Microsoft.Web/serverfarms/', parameters('hostingPlanName'))]",
                "hostingEnvironment": "[parameters('hostingEnvironment')]",
                "clientAffinityEnabled": true
            }
        }
    ]