Man pages matching name xkbfreegeomoverlaykeys in section 3:

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