I generated it through the command:

cvs2cl.pl --fsf -l "-d >2005-06-01"

The command cvs2cl.pl seems to be pretty standard (at least it is in the
debian official repository). Basically it uses the output from the cvs log
command -- so all the comments that we do when committing code.
The option "-d >2005-06-01" selects logs more recent than 2005-06-01.
Otherwise the file would get too large. The choice was completely
arbitrary.

Note than commiting a revision to the ChangeLog file, the way to do it
is in my opinion to commit it isolated (just the ChangeLog file), and
putting no log in the commit message (it is sort of redundant to log
the ChangeLog). Of course this first one is the exception.