As far as I know, trackmark names are listed in the "string-table" container of the config.txt file of the route or session if you rename them. If you leave the default name (or you cannot edit the route), they are not listed (not in any normally accessible file, at least).
I suppose TM names are stored in one of the the various files contained in the folder of a route or session. Examining them with a hexadecimal editor software might provide the required information, but it looks like a very hard and time-consuming task.