[ Filled as an RC-bug by the maintainer to see the package auto-removed
  from testing. ]

php-xml-htmlsax3 was packaged as a spip dependency, but the embedded
copy in SPIP is actually updated to work with recent versions of PHP,
while php-xml-htmlsax3 seems dead upstream. Since php-xml-htmlsax3 does
not have any other reverse-dependencies, the spip package now uses its
embedded up-to-date copy, and the php-xml-htmlsax3 package is now
useless.

I intend to follow up with an RM request in a few months if nobody
objects (but feel free to beat me to it).

Regards

David

Dear submitter,

as the package php-xml-htmlsax3 has just been removed from the Debian archive
unstable we hereby close the associated bug reports.  We are sorry
that we couldn't deal with your issue properly.

For details on the removal, please see https://bugs.debian.org/1014670

The version of this package that was in Debian prior to this removal
can still be found using http://snapshot.debian.org/.

Please note that the changes have been done on the master archive and
will not propagate to any mirrors until the next dinstall run at the
earliest.

This message was generated automatically; if you believe that there is
a problem with it please contact the archive administrators by mailing
ftpmaster@ftp-master.debian.org.

Debian distribution maintenance software
pp.
Thorsten Alteholz (the ftpmaster behind the curtain)