TreeLine is a versatile tool for working with all kinds of information
that fit into a tree-like structure.

It can be used to edit bookmark files, create mini-databases (for
example, for addresses, tasks, records, or CDs), outline documents, or
just collect ideas. It can also be used as a generic editor for XML
files.

The data schemas for any node in the data tree can be customized and
new types of nodes can be defined. The way data is presented on the
screen, exported to HTML, or printed can be defined with HTML-like
templates. Plug-ins can be written to load and save data from and to
custom file formats or external data sources and extend the
functionality of TreeLine.

TreeLine is written in Python and uses the PyQt bindings to the Qt
toolkit, which makes it very portable.