[mkgmap-dev] GRMN_TYPE

I was comparing a fairly new TYP  file (r4905 mapnik.txt) with my own (grown from Openfietsmap quite a while ago) and noticed there was usually a line like this ;GRMN_TYPE: Roads/HIGH_SPEED_RAMP, RAMP/Highway ramp which is to be driven at high speeds/Non NT, NT or ;GRMN_TYPE: // What is the meaning of this? Thx Brad