In fact, they are used. Probably, we should update and clarify this point in docs.
You use tabs as much as possible. To precisely align argument lists, you have
return_value very_long_function_name_bla_bla_bla(int first_argument,
int second_argument)
To make ’second_argument’ be under first, you should use 8 tabs + 1 space.
Overall, you can inspect other source files from box/ to understand how
source files should be formatted. Also, I advise you to make spaces and tabs visible.
For instance, see how it was done in box/space.c 106 : space_create()