Can someone explain to me this code under in steps? Thank you!

Question

a = [0, 1, 2, 3]

for a[-1] in a:
print (a[-1])

Answer 1

this code will iterate through the list four times as there are four items and will print all the numbers except the last number
as follow :
0
1
2
2 # not 3

Answer 2

And what does line 2 and 3 do?

Answer 3

Ahaa now I get it, thank you

Answer 4

But why it prints out 2 two times?