pdb3.9 - the Python debugger
pdb3.9 script [...]
See the chapter "The Python Debugger" in the Python Library Reference for more information on the use of pdb. When the debugger is started, help is available via the help command.
python3.9(1). Chapter "The Python Debugger" of the Python Library Reference. Available in the python3.9-doc package at /usr/share/doc/python3.9/html/library/pdb.html.