Man pages matching name xmvacreatemanagedpushbutton in section 3:

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