This is a very unique option added to FileBird which is useful by saving you a whole lot of time in creating folders from scratch again if you are switching from four other media library management plugins to FileBird. These five plugins are:
Enhanced Media Library by webbistro
WordPress Media Library Folders by Max Foundry
WordPress Real Media Library by devowl
WP Media Folder by JoomUnited
Happy Files by Thomas Ehrig
When you deactivate those plugins, FileBird can import all the folders you've created with them before and add them all as if they were folders originally created by FileBird. See image reference below for more information on how to do this:
However, please note that this option would not be available for you if FileBird does not detect the previous existence or installation of any fo these four plugins.