Man pages matching name xmvacreatesimplepulldownmenu in section 3:

XmVaCreateSimplePulldownMenu.3.en	debian 10 / libmotif-dev
XmVaCreateSimplePulldownMenu.3.en	debian 11 / libmotif-dev
XmVaCreateSimplePulldownMenu.3.en	debian 12 / libmotif-dev