Function Type shows that QUIT and EXIT are one object:

print (type (quit), type (exit))
# & lt; class '_sitebuiltins.quitter' & gt; & lt; class '_sitebuiltins.quitter' & gt;

function ID Returns different identifiers:

print (hex (id (quit), hex (ID (EXIT))
# 0x18caae42b70 0x18caae50630

function Help Returns the same description:

Help on Quitter in Module _sitebuiltins Object:
Class Quitter (Builtins.Object)
 | Methods Defined Here:
 |
 | __Call __ (Self, Code = None)
 | Call Self AS A FUNCTION.
 |
 | __init __ (Self, Name, EOF)
 | Initialize Self. See Help (Type (Self)) for Accurate Signature.
 |
 | __repr __ (Self)
 | RETURN REPR (SELF).
 |
 | ---------------------------------------------------- --------------------
 | Data Descriptors Defined Here:
 |
 | __dict__
 | Dictionary for Instance Variables (If Defined)
 |
 | __Weakref__
 | List of Weak References To The Object (If Defined)

in the documentation both functions have a general description

quit (code = none)
EXIT (Code = None)

Objects That WHEN Printed, Print A Message Like “Use Quit () or Ctrl-D (I.EOF)
to exit “, and when Called, Raise SystemexIt with the Specified Exit Code.

But the difference after all should be?

Answer 1, Authority 100%

short answer – no difference, these are objects from one class Quitter and the difference will be only in the name:

print (quit)
# USE Quit () or Ctrl-z Plus Return to EXIT
Print (EXIT)
# USE EXIT () or Ctrl-z Plus Return to EXIT

I think quit and exit added for the convenience of working with the interpreter.

For more understanding you need to see the source code _sitebuiltins.py :

class quitter (Object):
  Def __init __ (Self, Name, EOF):
    Self.name = Name.
    Self.eof = EOF.
  Def __repr __ (Self):
    RETURN 'USE% S () or% s to exit'% (self.name, self.eof)
  DEF __CALL __ (Self, Code = None):
    # Shells Like Idle Catch The SystemExit, But Listen WHEN THEIR
    # stdin wrapper is closed.
    Try:
      sys.stdin.close ()
    Except:
      Pass
    RAISE SYSTEMEXIT (Code)

as well as source code site.py :

def setquit ():
  "" "" Define New Builtins 'Quit' and 'Exit'.
  These Are Objects Which Make The Interpreter Exit When Called.
  The REPR OF EACH OBJECT CONTAINS A HINT AT How It Works.
  "" "
  if os.sep == '\\':
    eof = 'Ctrl-z plus Return'
  ELSE:
    eof = 'ctrl-d (i.e. eof)'
  builtins.quit = _sitebuiltins.quitter ('quit', eof)
  builtins.exit = _sitebuiltins.quitter ('exit', eof)

Similar answer to SO