Could you please add an id to the fieldset that controls the global account deletion function in Special:CentralAuth? (Bonus: id all fieldsets for that special page, and also the buttons).
Some fieldsets for that page already have an ID e.g. SpecialCentralAuth.php Line 391 generates a <fieldset id = "mw-centralauth-info"> which allows users to customise that special page functionality through personal JS / CSS.
The delete action fieldset seems to be controled by Line 930 et seq. of SpecialCentralAuth.php
Thank you.