This has partly been requested by nod5 so he can improve his highlight helper, however I think its very low on the list of priorities, unless exposing some API allows that info.
You could use AutoHotKey to collect and display/save that info and if you do / can get someone to develop a few ahk lines that help others to do the same please feel free to show them back here.
Anyway I think the starting point from nod5s ahk code is
ControlGetText, xpos, SUMATRA_PDF_NOTIFICATION_WINDOW1, A
if (xpos != “” and InStr(xpos,“pt”) != 0 ) ;need pos in pt measure, not mm or in
Or use his donationware helper to save highlighted blocks to the .smx and convert that textual output.