In : a, *b, c = range(5)
In : a, c
Out: (0, 4)
In : b
Out: [1, 2, 3]
In : *a, = range(5)
In : a
Out: [0, 1, 2, 3, 4]
In : for a, *b in [(1, 2, 3), (4, 5, 6, 7)]:
...:   print(b)
...:
[2, 3]
[5, 6, 7]

In : def a():
...:   rest = (4, 5, 6)
...:   t = 1, 2, 3, *rest
...:   return t
...:

In : for i in a():
...:   print(i)
...:

In : (1, 2, 3) + (3, 4, 5, 6)
Out: (1, 2, 3, 4, 5, 6)

In : def b():
...:   rest = (4, 5, 6)
...:   return 1, 2, 3, *rest
File "<ipython-input-38-b5a7115853e2>", line 3
 return 1, 2, 3, *rest
          ^
SyntaxError: invalid syntax

In : def c():
...:   rest = (4, 5, 6)
...:   yield 1, 2, 3, *rest
File "<ipython-input-39-cf6991fcff64>", line 3
 yield 1, 2, 3, *rest
          ^
SyntaxError: invalid syntax
Python 3.8

> def b():
...   rest = (4, 5, 6)
...   return 1, 2, 3, *rest
...
> for i in b():
...   print(i)
...
> def c():
...   rest = (4, 5, 6)
...   yield 1, 2, 3, *rest
...
> for i in c():
...   print(i)
...
(1, 2, 3, 4, 5, 6)