Man pages matching name xmvacreatemanageddatafield in section 3:

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