Staff action logs explain when system is deleting a post because author marked it to be deleted

config/locales/server.en.yml

@@ -53,6 +53,7 @@ en:
   purge_reason: "Automatically deleted as abandoned, deactivated account"
   disable_remote_images_download_reason: "Remote images download was disabled because there wasn't enough disk space available."
   anonymous: "Anonymous"
+  remove_posts_deleted_by_author: "Deleted by author"
 
   emails:
     incoming:

lib/post_destroyer.rb

@@ -29,7 +29,7 @@ class PostDestroyer
                         pa.post_action_type_id IN (?)
               )", PostActionType.notify_flag_type_ids)
         .each do |post|
-      PostDestroyer.new(Discourse.system_user, post).destroy
+      PostDestroyer.new(Discourse.system_user, post, {context: I18n.t('remove_posts_deleted_by_author')}).destroy
     end
   end