mb event system 3 Sections EventSystems Doc
IF YOU CAN SEE THIS go to /sfa/Nuprl/Shared/Xindentation_hack_doc.html
Def tag(k) == 2of(outl(k))

is mentioned by

Def msg(a) == msg(lnk(kind(a));tag(kind(a));val(a))[w-msg]

In prior sections: mb event system 2

Try larger context: EventSystems IF YOU CAN SEE THIS go to /sfa/Nuprl/Shared/Xindentation_hack_doc.html

mb event system 3 Sections EventSystems Doc