Flagged Files

Oracle EBS has a feature to flag files that you have customized. This feature is aptly named "Flagged Files". You can flag these files in EBS itself starting at the System Administrator responsibility:

System Administrator -> Oracle Applications Manager -> Dashboard
Site Map -> Maintenance -> Register Flagged Files

After that, when you've installed a patch you can run below query to give you an idea about which of the flagged files have been touched. Based in the result of the query, you can then inspect your customizations and see if they are still required. If that is the case, you can verify their presence and inner workings.

select bugs.orig_bug_number,
       fils.app_short_name || ' ' || fils.subdir || '/' || fils.filename touched_file,
       fils.flagged_file_comments
  from ad_patch_run_bugs bugs, ad_patch_run_bug_actions acti, ad_files fils
 where bugs.patch_run_id in --
       (select runs.patch_run_id
          from ad_patch_runs         runs,
               ad_patch_drivers      driv,
               ad_applied_patches    patc,
               ad_patch_driver_langs lang,
               ad_comprising_patches acp,
               ad_bugs               ab
         where runs.last_update_date > trunc(sysdate - &p_days_back)
           and driv.patch_driver_id = runs.patch_driver_id
           and driv.applied_patch_id = patc.applied_patch_id
           and driv.patch_driver_id = lang.patch_driver_id
           and driv.patch_driver_id = acp.patch_driver_id(+)
           and acp.bug_id = ab.bug_id(+))
   and bugs.patch_run_bug_id = acti.patch_run_bug_id
   and acti.file_id = fils.file_id
   and acti.executed_flag = 'Y'
   and fils.is_flagged_file = 'Y'
 group by bugs.orig_bug_number,
          fils.app_short_name || ' ' || fils.subdir || '/' || fils.filename,
          fils.flagged_file_comments;

Should the customization no longer be present, dont forget to remove the flag from the file in the "Flagged Files"!