PowerBuilder libraries – PB Docs 2022

As you work in an application, component, or .NET target, the
objects you create are stored in one or more libraries (PBL files)
associated with the application. When you run your application,
PowerBuilder retrieves the objects from the library.

PowerBuilder provides a Library painter for managing your
libraries. For information about creating a new library and working
with libraries in the Library painter, see Working with Libraries.