The Proofscape Integrated Study Environment – “PISE” for short – is
like an IDE (integrated development environment) for the proofscape
language. But the emphasis is on helping you study mathematics, hence
the name.
The PBE puts the PDFs in PISE.
You can use the Proofscape Browser Extension to make PDFs load
automatically and effortlessly in PISE (thus avoiding tedious manual
download and selection from file-chooser dialogs).