Version 10 is the first frozen version.  No more changes except for critical bug fixes.
version10.zip includes both test programs.  The smaller one corresponds to the sample program.  The other one includes a lot of extra test capabilities.
version10.zip also includes the jar files that E*TRADE will need to distribute with their client.
The API_sample_program and javadoc directories contain the samples and documentation for the E*TRADE developers.  These have not changed since they were originally released.