tinangel/ShaderTools — comment on commit f9c8b6e1f89e0289412ef7e3804770f5be607c79
File:  line 0
By ldo:

Using negative indexes is a standard feature of Python arrays; it means indexing from the other end, i.e. -1 for the last element, -2 for the second-to-last etc. Saves a lot of effort, don’t you think. :)