(A quite late followup to T238425)
Vague idea to run read-only SQL queries to potentially clean up Phab project page sidebar menu items (like querying for duplicated "Open Tasks" items which we do have due to manual creation before that item became an upstream default built-in one), also cf https://secure.phabricator.com/T7410 or T105865 here when it comes to workboard menu items when workboards just aren't used.
Project page menu items are stored in the phabricator_search.search_profilepanelconfiguration table. (Yeah, not very obvious.)