default-left-fringe-width

default-left-fringe-width is a variable defined in `C source code'.
Its value is

nil

• This variable is obsolete since 23.2;
  use `left-fringe-width' instead.

Documentation:
Default value of `left-fringe-width' for buffers that don't override it.
This is the same as (default-value 'left-fringe-width).