These fields were migrated to event_page_id in production in 2013, but were then never dropped.
SQL:
- https://phabricator.wikimedia.org/diffusion/ECHO/browse/master/db_patches/patch-drop-echo_event-event_page_namespace.sql
- https://phabricator.wikimedia.org/diffusion/ECHO/browse/master/db_patches/patch-drop-echo_event-event_page_title.sql
Where: all x1 databases that have an echo_event table (same set as echo.dblist)
Backwards compatible: yes, now that the patch is merged the software doesn't reference these fields anymore