I've replaced one edition of https://www.cpdl.org/wiki/index.php/Pro ... ume_Dufay) and modeled my effort on the code at https://www.cpdl.org/wiki/index.php/Lam ... ecquillon), which also has the unsightly hanging braces }}
ShowEdition seems to be invoked by :Edition, but neither is listed at https://www.cpdl.org/wiki/index.php/Category:Templates where there's confusion over which of Template:Withdrawn, Template:WithdrawnNotice and Template:WithdrawnByComp are current. May I ask someone to write an overview at Help:Withdrawn?