/usr/share/php/Composer/Package/Archiver/ is in composer 1.6.3-1.
This file is owned by root:root, with mode 0o755.
..
/usr/share/php/Composer/Package/Archiver/ArchivableFilesFilter.php
/usr/share/php/Composer/Package/Archiver/ArchivableFilesFinder.php
/usr/share/php/Composer/Package/Archiver/ArchiveManager.php
/usr/share/php/Composer/Package/Archiver/ArchiverInterface.php
/usr/share/php/Composer/Package/Archiver/BaseExcludeFilter.php
/usr/share/php/Composer/Package/Archiver/ComposerExcludeFilter.php
/usr/share/php/Composer/Package/Archiver/GitExcludeFilter.php
/usr/share/php/Composer/Package/Archiver/HgExcludeFilter.php
/usr/share/php/Composer/Package/Archiver/PharArchiver.php
/usr/share/php/Composer/Package/Archiver/ZipArchiver.php