Add details about expanded logging for LLM.log

doc/administration/logs/index.md

@@ -1029,9 +1029,26 @@ DETAILS:
 > - [Introduced](https://gitlab.com/gitlab-org/gitlab/-/merge_requests/120506) in GitLab 16.0.
 
 The `llm.log` file logs information related to
-[AI features](../../user/ai_features.md).
+[AI features](../../user/ai_features.md). Logging includes information about AI events. 
 
-This file is located at:
+### LLM input and output logging
+
+> - [Introduced](https://gitlab.com/groups/gitlab-org/-/epics/13401) in GitLab 17.2 [with a flag](../../administration/feature_flags.md) named `expanded_ai_logging`. Disabled by default.
+
+FLAG:
+The availability of this feature is controlled by a feature flag.
+For more information, see the history.
+This feature is available for testing, but not ready for production use.
+
+LLM prompt input and response output can be logged by enabling the `expanded_ai_logging` feature flag.
+This flag is disabled by default and can only be enabled:
+
+- For GitLab.com, when you provide consent through a GitLab [Support Ticket](https://about.gitlab.com/support/portal/).
+- For self-managed, when you enable this feature flag.
+
+By default, the log does not contain LLM prompt input and response output to support [data retention policies](../../user/gitlab_duo/data_usage.md#data-retention) of AI feature data. 
+
+The log file is located at:
 
 - `/var/log/gitlab/gitlab-rails/llm.log` on Linux package installations.
 - `/home/git/gitlab/log/llm.log` on self-compiled installations.

doc/user/gitlab_duo/data_usage.md

@@ -34,7 +34,7 @@ The below reflects the current retention periods of GitLab AI model [Sub-Process
 
 All of these AI providers are under data protection agreements with GitLab that prohibit the use of Customer Content for their own purposes, except to perform their independent legal obligations.
 
-GitLab does not retain input and output data unless customers provide consent through a GitLab [Support Ticket](https://about.gitlab.com/support/portal/).
+GitLab does not retain input and output data unless customers provide consent through a GitLab [Support Ticket](https://about.gitlab.com/support/portal/). Learn more about [AI feature logging](../../administration/logs/index.md).
 
 ## Training data