This file exists only during a host run. It contains the future util.dat files' contents, just like mess.tmp contains messages that will be in the RSTs.
Like util.dat, this file is structured in records. In PHost 3.4 and above, the format is as follows:
+0 WORD Player Id (whose UTILx.DAT file will contain this data) +2 WORD Record Type (like in UTILx.DAT) +4 WORD Record Length +6 n BYTEs Data
