These are sanitized cache access logs provided by the National Laboratory for Applied Network Research in the hope they may be useful for researchers and developers. NLANR is not in a position to operationally provide such information, and, if circumstances require, will cease making data available.
If you use this data for research or commercial purposes, you must give a credit reference to the National Science Foundation (grants NCR-9616602 and NCR-9521745), and the National Laboratory for Applied Network Research.
These traces are stored as plain text, and so can be read through any standard text processing library. The README contains the trace format.