The files were generated with the CRM 4.0 SDK (the CrmDateTime
rang a bell).
With the CrmSvcUtil.exe
from the CRM 4.0 SDK it is possible to generate separate files, as documented here:
http://msdn.microsoft.com/en-us/library/ff681563.aspx
/out parameter
Determines the name of the .cs or .xml output file and whether there is one file or one per entity. It may include a full path. If you specify a name that does not end with .cs or .xml, CrmSvcUtil will write an individual .cs file for every entity in the system to the folder you specify. For example, /out:MyClasses outputs a class file (.cs) for every entity to a folder called MyClasses.However, /out:MyClasses.cs outputs a class file (MyClasses.cs) that contains all entities.
This "feature" has been removed from CRM 2011 SDK (if you try to specify the name without the file extension it will still generate a single file)