**What APT affects:**
* package/service/configuration files for APT
+ * NOTE: Setting the `purge_preferences` or `purge_preferences_d` parameters to 'true' will destroy any existing configuration that was not declared with puppet. The default for these parameters is 'false'.
* your system's `sources.list` file and `sources.list.d` directory
* NOTE: Setting the `purge_sources_list` and `purge_sources_list_d` parameters to 'true' will destroy any existing content that was not declared with Puppet. The default for these parameters is 'false'.
* system repositories
Puppet will manage your system's `sources.list` file and `sources.list.d` directory but will do its best to respect existing content.
-If you declare your apt class with `purge_sources_list` and `purge_sources_list_d` set to 'true', Puppet will unapologetically purge any existing content it finds that wasn't declared with Puppet.
+If you declare your apt class with `purge_sources_list`, `purge_sources_list_d`, `purge_preferences` and `purge_preferences_d` set to 'true', Puppet will unapologetically purge any existing content it finds that wasn't declared with Puppet.
### apt::builddep