How can I display a list in reverse with 3 colon-separators?

You should omit 0 here:

print(list[-1:0:-1])

and write it as

print(list[-1::-1])

or place None:

print(list[-1:None:-1])

The reason is: when you omit the stop value (or substitute None) in a "3 colon-seperators", this will happen:

If i or j are omitted or None, they become “end” values (which end depends on the sign of k).

where j here corresponds to the stop value (and i is the start i.e. [i:j:k])

Use None:

>>> list[-1:None:-1]
[10, 9, 8, 7, 6, 5, 4, 3, 2, 1]

or

>>> list[None:None:-1]
[10, 9, 8, 7, 6, 5, 4, 3, 2, 1]

You could use -len(list)-1, but None is simpler and doesn't require any computation.

BTW list is a bad variable name since it shadows the builtin list.

You can use following ways of list slicing to achieve required result.

list = [1,2,3,4,5,6,7,8,9,10]

#Use Blank:
print(list[::-1])
print(list[-1::-1])
#output
#[10, 9, 8, 7, 6, 5, 4, 3, 2, 1]

#Use None:
print(list[:None:-1])
print(list[None:None:-1])
#output
#[10, 9, 8, 7, 6, 5, 4, 3, 2, 1]

#Use Boolean:
print(list[-True::-True])
#output
#[10, 9, 8, 7, 6, 5, 4, 3, 2, 1]

#Use Boolean:
print(list[~False::-1])
#output
#[10, 9, 8, 7, 6, 5, 4, 3, 2, 1]


#Use of Length function:
print(list[:-(len(list)+1):-1])
#output
#[10, 9, 8, 7, 6, 5, 4, 3, 2, 1]