Auto panes provides two features:
If enabled in settings, auto-close will save and close all existing editors when you open a file.
If enabled in settings, auto-open will spawn panes for all existing files in the same folder with the same name as the file you selected for main view.
This is useful for working with related files such as css/js/html, coffee/jade/stylus etc.
The package can be quickly toggled on and off with a key binding or menu command
Good catch. Let us know what about this package looks wrong to you, and we'll investigate right away.