/usr/share/qgis/python/pyplugin_installer/ is in python-qgis-common 2.0.1-2build2.
This file is owned by root:root, with mode 0o755.
..
/usr/share/qgis/python/pyplugin_installer/__init__.py
/usr/share/qgis/python/pyplugin_installer/installer.py
/usr/share/qgis/python/pyplugin_installer/installer_data.py
/usr/share/qgis/python/pyplugin_installer/qgsplugininstallerfetchingdialog.py
/usr/share/qgis/python/pyplugin_installer/qgsplugininstallerinstallingdialog.py
/usr/share/qgis/python/pyplugin_installer/qgsplugininstallerpluginerrordialog.py
/usr/share/qgis/python/pyplugin_installer/qgsplugininstallerrepositorydialog.py
/usr/share/qgis/python/pyplugin_installer/ui_qgsplugininstallerfetchingbase.py
/usr/share/qgis/python/pyplugin_installer/ui_qgsplugininstallerinstallingbase.py
/usr/share/qgis/python/pyplugin_installer/ui_qgsplugininstallerpluginerrorbase.py
/usr/share/qgis/python/pyplugin_installer/ui_qgsplugininstallerrepositorybase.py
/usr/share/qgis/python/pyplugin_installer/unzip.py
/usr/share/qgis/python/pyplugin_installer/version_compare.py