Doc fixes (2026-10-06) (#917)

* concepts/pipeline/data_pipeline_detail.md: Add obsolete banner

Finding-Id: ef30bafb3af7452790f12d75b86f3025
Reviewed: no (this PR is the review)

* datasets/obsolete/activity-stream/reference.md: Add obsolete banner

Finding-Id: bb228efbaa8949f48f846145d57f62bc
Reviewed: no (this PR is the review)

* datasets/obsolete/legacy_mobile/reference.md: Add obsolete banner

Finding-Id: 3aa7677bbc3a46e2b5d0b416c7f919fb
Reviewed: no (this PR is the review)

* cookbooks/looker/performance_caching.md: Update stale datagroup example to current name

Finding-Id: 7cbcb738efe64c4faaa0c9b2a42bf267
Reviewed: no (this PR is the review)
Source: https://github.com/mozilla/looker-hub/blob/main/search/explores/mobile_search_counts.explore.lkml
Source: https://github.com/mozilla/looker-hub/tree/HEAD/search/datagroups

* datasets/search/search_clients_last_seen/reference.md: Note default view still serves v1, v2 exists for LTV

Finding-Id: f5299f9284974e7f970d245cc336b54c
Reviewed: no (this PR is the review)
Source: https://github.com/mozilla/bigquery-etl/blob/main/sql/moz-fx-data-shared-prod/search/search_clients_last_seen/view.sql
Source: https://github.com/mozilla/bigquery-etl/blob/main/sql/moz-fx-data-shared-prod/search_derived/search_clients_last_seen_v2/metadata.yaml

* concepts/pipeline/data_pipeline_detail.md: Fix dead Presto link

---------

Co-authored-by: doc-correctness <doc-correctness@users.noreply.github.com>

Author: scholtzan

src/concepts/pipeline/data_pipeline_detail.md

@@ -1,5 +1,7 @@
 # A Detailed Look at the Data Platform
 
+> This page is obsolete and is no longer maintained. It is kept for historical reference; do not use it for new work.
+
 For a more gentle introduction to the data platform, please read the [Pipeline Overview](data_pipeline.md) article.
 
 This article goes into more depth about the architecture and flow of data in the platform.
@@ -391,7 +393,7 @@ graph LR
 [metrics graphics]: http://metricsgraphicsjs.org/
 [parquet]: https://parquet.apache.org/
 [hive]: https://cwiki.apache.org/confluence/display/Hive/Home
-[presto]: http://prestosql.io/
+[presto]: https://trino.io/
 [telemetry aggregates]: https://github.com/mozilla/python_mozaggregator/#api
 [amazon s3]: https://aws.amazon.com/s3/
 [taar project]: https://github.com/mozilla/python_mozetl/blob/master/mozetl/taar/taar_dynamo.py

src/cookbooks/looker/performance_caching.md

@@ -31,19 +31,19 @@ See the following example:
 
 ```
 ...
-include: "//looker-hub/search/datagroups/mobile_search_clients_daily_v1_last_updated.datagroup.lkml"
+include: "//looker-hub/search/datagroups/mobile_search_clients_engines_sources_daily_last_updated.datagroup.lkml"
 
 explore: mobile_search_counts {
 
   ...
 
-  persist_with: mobile_search_clients_daily_v1_last_updated
+  persist_with: mobile_search_clients_engines_sources_daily_last_updated
 
 }
 
 ```
 
-Now, query results for the `Mobile Search Counts` explore will be cached until the `mobile_search_clients_daily_v1`
+Now, query results for the `Mobile Search Counts` explore will be cached until the `mobile_search_clients_engines_sources_daily`
 table is updated and users running the same query will receive fast results (a few seconds usually).
 
 If you aren't able to find an auto-generated datagroup or your explore has multiple, complex joins, move on to

src/datasets/obsolete/activity-stream/reference.md

@@ -1,5 +1,7 @@
 # Activity Stream Datasets
 
+> This dataset is obsolete and is no longer maintained. It is kept for historical reference; do not use it for new analyses.
+
 This article describes the various BigQuery tables Mozilla uses to store Activity Stream data, along with some examples of how to access them.
 
 ## Table of Contents

src/datasets/obsolete/legacy_mobile/reference.md

@@ -1,5 +1,7 @@
 # Legacy Mobile Datasets
 
+> This dataset is obsolete and is no longer maintained. It is kept for historical reference; do not use it for new analyses.
+
 Modern mobile products use the [Glean SDK] and are thus documented by the [Glean Dictionary].
 This documentation documents some details about accessing data for legacy products based on other technology.
 

src/datasets/search/search_clients_last_seen/reference.md

@@ -28,7 +28,10 @@ This dataset is scheduled on Airflow
 ## Schema
 
 As of 2020-04-22, the current version of `search_clients_last_seee` is `v1`,
-and has a schema as follows.
+and has a schema as follows. The default `search.search_clients_last_seen`
+view still returns this `v1` schema; a newer `v2` version with a different
+schema (described below) also exists and is used as the basis for LTV
+calculations.
 It's backfilled through 2020-01-01
 
 ```