:61758723 Well, \xmapsto seems to work OK. Defined in math-stc.mkxl as `\definemathextensible [\v!reverse] [xmapsto] ["21A6]`. In the unpacked lucida math font one can find (not sure that it helps though):
[8614]={
["boundingbox"]=84,
["index"]=411,
["math"]={
["hparts"]={
{
["advance"]=211,
["end"]=161,
["glyph"]=983125,
["start"]=0,
},
{
["advance"]=457,
["end"]=457,
["extender"]=1,
["glyph"]=983122,
["start"]=457,
},
{
["advance"]=814,
["end"]=0,
["glyph"]=983127,
["start"]=457,