Clarify what missing members article is about (#44400)

Author: gewarren

docs/core/whats-new/dotnet-8/runtime.md

@@ -170,7 +170,7 @@ Required modifier for first parameter: System.Runtime.InteropServices.InAttribut
 
 ### Serialization
 
-Many improvements have been made to <xref:System.Text.Json?displayProperty=fullName> serialization and deserialization functionality in .NET 8. For example, you can [customize handling of members that aren't in the JSON payload](../../../standard/serialization/system-text-json/missing-members.md).
+Many improvements have been made to <xref:System.Text.Json?displayProperty=fullName> serialization and deserialization functionality in .NET 8. For example, you can [customize handling of JSON properties that aren't in the POCO](../../../standard/serialization/system-text-json/missing-members.md).
 
 The following sections describe other serialization improvements:
 

docs/fundamentals/toc.yml

@@ -745,7 +745,7 @@ items:
                         href: ../standard/serialization/system-text-json/nullable-annotations.md
                       - name: Allow invalid JSON
                         href: ../standard/serialization/system-text-json/invalid-json.md
-                      - name: Handle missing members
+                      - name: Handle unmapped members
                         href: ../standard/serialization/system-text-json/missing-members.md
                       - name: Handle overflow JSON, use JsonElement or JsonNode
                         href: ../standard/serialization/system-text-json/handle-overflow.md

docs/standard/serialization/system-text-json/missing-members.md

@@ -1,17 +1,17 @@
 ---
-title: Handle missing members during deserialization
+title: Handle unmapped members during deserialization
 description: "Learn how to configure the JSON deserialization behavior when properties are present in the JSON payload that aren't present in the POCO type."
-ms.date: 03/01/2023
+ms.date: 01/15/2025
 no-loc: [System.Text.Json]
 dev_langs:
   - "csharp"
 ---
 
-# Handle missing members during deserialization
+# Handle unmapped members during deserialization
 
-By default, if the JSON payload you're deserializing contains properties that don't exist in the deserialized plain old CLR object (POCO) type, they're simply ignored. Starting in .NET 8, you can specify that all members must be present in the payload. If they're not, a <xref:System.Text.Json.JsonException> exception is thrown. You can configure this behavior in one of three ways:
+By default, if the JSON payload you're deserializing contains properties that don't exist in the plain old CLR object (POCO) type, they're simply ignored. Starting in .NET 8, you can specify that *all payload properties must exist in the POCO*. If they're not, a <xref:System.Text.Json.JsonException> exception is thrown during deserialization. You can configure this behavior in one of three ways:
 
-- Annotate your POCO type with the <xref:System.Text.Json.Serialization.JsonUnmappedMemberHandlingAttribute> attribute, specifying either to <xref:System.Text.Json.Serialization.JsonUnmappedMemberHandling.Skip> or <xref:System.Text.Json.Serialization.JsonUnmappedMemberHandling.Disallow> missing members.
+- Annotate your POCO type with the <xref:System.Text.Json.Serialization.JsonUnmappedMemberHandlingAttribute> attribute, specifying either to <xref:System.Text.Json.Serialization.JsonUnmappedMemberHandling.Skip> or <xref:System.Text.Json.Serialization.JsonUnmappedMemberHandling.Disallow> unmapped members.
 
   ```csharp
   [JsonUnmappedMemberHandling(JsonUnmappedMemberHandling.Disallow)]