diff -u b/core/modules/migrate/src/Plugin/MigrateSourceInterface.php b/core/modules/migrate/src/Plugin/MigrateSourceInterface.php
--- b/core/modules/migrate/src/Plugin/MigrateSourceInterface.php
+++ b/core/modules/migrate/src/Plugin/MigrateSourceInterface.php
@@ -86,8 +86,8 @@
    *   Additional custom keys/values, that are not part of field storage
    *   definition, can be passed in definitions. The most common setting, passed
    *   along the ID definition, is 'alias' used by SqlBase source plugin to
-   *   distinguish between ambiguous column names- for example, when a SQL source
-   *   query joins two tables with the same column names.
+   *   distinguish between ambiguous column names - for example, when a SQL
+   *   source query joins two tables with the same column names.
    *   @code
    *     return [
    *       'nid' => [