diff -u b/core/modules/migrate/src/Plugin/migrate/process/MigrationLookup.php b/core/modules/migrate/src/Plugin/migrate/process/MigrationLookup.php
--- b/core/modules/migrate/src/Plugin/migrate/process/MigrationLookup.php
+++ b/core/modules/migrate/src/Plugin/migrate/process/MigrationLookup.php
@@ -17,8 +17,7 @@
  * Looks up the value of a property based on a previous migration.
  *
  * It is important to maintain relationships among content coming from the
- * source site, but in most instances the unique identifiers of the content
- * change in the process of migration. For example, on the source site, a given
+ * source site. For example, on the source site, a given
  * user account may have an ID of 123, but the Drupal user account created from
  * it may have a uid of 456. The migration process maintains the relationships
  * between source and destination identifiers in map tables, and this
@@ -86,8 +85,8 @@
  *     stub_id: members
  * @endcode
  *
- * Here, the value of stub_id selects the members migration to create any stub
- * entities.
+ * In the above example, the value of stub_id selects the members migration to
+ * create any stub entities.
  *
  * To prevent the creation of a stub entity when no relationship is found in the
  * migration map, use no_stub:
diff -u b/core/modules/migrate/tests/src/Unit/process/MigrationTest.php b/core/modules/migrate/tests/src/Unit/process/MigrationTest.php
--- b/core/modules/migrate/tests/src/Unit/process/MigrationTest.php
+++ b/core/modules/migrate/tests/src/Unit/process/MigrationTest.php
@@ -18,7 +18,7 @@
 
 /**
  * @deprecated in Drupal 8.4.x, to be removed before Drupal 9.0.x. Use
- *   \Drupal\Tests\migrate\Unit\processMigrationLookupTest instead.
+ *   \Drupal\Tests\migrate\Unit\process\MigrationLookupTest instead.
  *
  * @coversDefaultClass \Drupal\migrate\Plugin\migrate\process\Migration
  * @group migrate