Man pages matching name xkbsasetptrdfltvalue in section 3:

XkbSASetPtrDfltValue.3.en	debian 10 / libx11-doc
XkbSASetPtrDfltValue.3.en	debian 11 / libx11-doc
XkbSASetPtrDfltValue.3.en	debian 12 / libx11-doc