WordPress and umask

Been looking through as much of the code as I can, but I’m still relatively new to both WordPress and php in general. What is WordPress using for a umask value whenever it uploads/installs content, plugins, etc?

For instance, checking the plugin installation – WordPress appears to set the permissions for new plugin folders to 755 no matter what I do. I have tried setting a general umask value for my system; tried setting a umask value for apache specifically (which is what is currently running the application). Same for the owner of the files, the location of the files, and every instance of the php umask command I can find:

wp-admin/includes/class-ftp.php
wp-admin/includes/upgrade.php

I’m sure it is something I have already tried to tinker with and simply did it incorrectly, but if someone could point me in the exact location for what is setting these permissions, that would be awesome. Thanks.