# Part IV. Abstraction Layer

In order to hide the internals of the file manager from the extensions, the `thunarx` library provides an abstraction layer, which includes interfaces accessible to the extension, that are implemented by the file manager at runtime.

Currently the abstraction layer consists of the interface ThunarxFileInfo, which provides extensions with a way to access information about a file handled within the file manager, the class ThunarxPropertyPage, which is the base class for widgets that can be added to the properties dialog by extensions, the interface ThunarxProviderPlugin, which hides the details of dynamic type registration from the extensions, and the class ThunarxRenamer, which is the abstract base class for renamers that can be used in the bulk rename dialog provided by Thunar to rename multiple files at once.