This documentation change includes the following:

* Updated language in `/programming-guides/editions.md`
* Fixing a link in `/reference/go/go-generated-opaque.md`
* Adding an explanation of default behavior for presence to the `/programming-guides/field_presence.md` topic.

PiperOrigin-RevId: 712523304
Change-Id: Ia2dd5518a91f8cd77431c924c6dbdb56b4189ad7

Author: Protocol Buffer Team

content/programming-guides/editions.md

@@ -1495,9 +1495,9 @@ language in the relevant [API reference](/reference/).
     ```
 
 *   If the parser encounters multiple members of the same oneof on the wire,
-    only the last run of the last member seen is used in the parsed message.
-    When parsing data on the wire, starting at the beginning of the bytes,
-    evaluate the next value, and apply the following parsing rules:
+    only the last member seen is used in the parsed message. When parsing data
+    on the wire, starting at the beginning of the bytes, evaluate the next
+    value, and apply the following parsing rules:
 
     *   First, check if a *different* field in the same oneof is currently set,
         and if so clear it.

content/programming-guides/field_presence.md

@@ -179,6 +179,12 @@ basic types (numeric, string, bytes, and enums), either. Oneof fields
 affirmatively expose presence, although the same set of hazzer methods may not
 generated as in proto2 APIs.
 
+This default behavior of not tracking presence without the `optional` label is
+different from the proto2 behavior. We reintroduced
+[explicit presence](/editions/features#field_presence) as
+the default in edition 2023. We recommend using the `optional` field with proto3
+unless you have a specific reason not to.
+
 Under the *implicit presence* discipline, the default value is synonymous with
 "not present" for purposes of serialization. To notionally "clear" a field (so
 it won't be serialized), an API user would set it to the default value.

content/reference/go/go-generated-opaque.md

@@ -175,7 +175,7 @@ protoc […] --go_opt=default_api_level=API_HYBRID
 
 To override the default API level for a specific file (instead of all files),
 use the `apilevelM` mapping flag (similar to [the `M` flag for import
-paths](/reference/go/go-generated/#package)):
+paths](#package)):
 
 ```
 protoc […] --go_opt=apilevelMhello.proto=API_HYBRID