Should packages with PPA lineages preserve their PPA changelogs?

[Scott Ritchie]

If we start with foo 1.0-0ubuntu1 in the archive, and I make a PPA fork
for foo 1.1-0ubuntu1, and end up going through multiple PPA revisions
(say, foo 1.1-0ubuntu1~ppa1 through 1.1-0ubuntu1~ppa6), should the
changelog entries for those revisions end up in the final upload to
Ubuntu proper?  Or should I purge them and keep the changelog "pure" to
real Ubuntu uploads?  Or should their content be merged somehow?

Thanks,
Scott Ritchie