for i in range(10,0,-1):

This Python code will iterate from 10 to 1 (inclusive) in descending order, with a step of -1.

Here's an example of how you could use this code:

for i in range(10,0,-1):
    print(i)

This would output:

10
9
8
7
6
5
4
3
2
1

In this example, the `range()` function creates a sequence of numbers from 10 to 1, with a step of -1. The `for` loop then iterates through each number in the sequence, and the `print()` function displays the number on the screen.