The trackDb.txt file, which is based on the Genome Browser .ra format, is the most complex of the text files in the hub directory. It contains a collection of stanzas, one for each data file in a given assembly, that define the display and configuration properties for each track or group of tracks (in the case of composite or super-tracks). The Track Database Definition document (http://genome.ucsc.edu/goldenPath/help/trackDb/trackDbHub.html) provides details about how to declare the dataset display settings and values used in trackDb.txt.
