Man pages matching name xmcvtcttoxmstring in section 3:

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