The package enables the user to connect information, and to
place labels, without knowing (in advance) the actual positions
of the items to be connected, or where the connecting line
should go. The macros are useful for making graphs and trees,
mathematical diagrams, linguistic syntax diagrams, and so on.
The package contents were previously distributed as a part of
the pstricks base distribution; the package serves as an
extension to PSTricks.

Homepage:
https://ctan.org/pkg/pst-node
