This node:

https://www.openstreetmap.org/node/62479515

has highway=motorway_junction and noref=yes

and my line file contains:

# build exit hint 
exit_hint=* { delete exit_hint }
(highway=motorway_link | highway=trunk_link | highway=primary_link | highway=secondary_link | highway=tertiary_link) & mkgmap:exit_hint=true 
  { set exit_hint = 'Exit ${mkgmap:exit_hint_ref}';
# 'Exit ${mkgmap:exit_hint_name|subst: Road=> Rd|subst: Street=> St|subst: Avenue=> Ave|subst: Mile=> Mi|subst: Boulevard=> Blvd|subst: Parkway=> Pkwy|subst: Highway=> Hwy}' | 
# 'Exit ${ref|subst: South=> S|subst: North=> N|subst: East=> E|subst: West=> W}' |
# 'Exit ${mkgmap:exit_hint_ref|subst: South=> S|subst: North=> N|subst: East=> E|subst: West=> W} ${mkgmap:exit_hint_exit_to|subst: Road=> Rd|subst: Street=> St|subst: Avenue=> Ave|subst: Mile=> Mi|subst: Boulevard=> Blvd|subst: Parkway=> Pkwy|subst: Highway=> Hwy}' | 
# 'Exit ${mkgmap:exit_hint_exit_to|subst: Road=> Rd|subst: Street=> St|subst: Avenue=> Ave|subst: Mile=> Mi|subst: Boulevard=> Blvd|subst: Parkway=> Pkwy|subst: Highway=> Hwy}' |
# 'Exit ${mkgmap:exit_hint_name|subst: Road=> Rd|subst: Street=> St|subst: Avenue=> Ave|subst: Mile=> Mi|subst: Boulevard=> Blvd|subst: Parkway=> Pkwy|subst: Highway=> Hwy}' |
# 'Exit ${mkgmap:exit_hint_ref|subst: South=> S|subst: North=> N|subst: East=> E|subst: West=> W}';

The resulting EXIT and MOTORWAY_LINK info builds this string:

Exit Noref Wiard Rd-Willow Run Airport

Since there is NO ref= tag, which one of the mkgmap variables is being set to NOREF.
I want to write code to blank out the NOREF.

thanks
Greg