Point it at any project with a main.py. It runs your app as a child process, watches source files, hot-patches live edits, captures crashes, manages interpreters and dependencies, builds an EXE, and ...
NEW: Thonny now runs in single instance mode. Previously, when you opened a py file with Thonny, a new Thonny instance (window) was created even if an instance existed already. This became nuisance if ...