whitespace-space-after-tab

whitespace-space-after-tab is a variable defined in `whitespace.el'.
Its value is

whitespace-space-after-tab

• This variable is obsolete since 24.4;
  use the face instead.

Documentation:
Symbol face used to visualize 8 or more SPACEs after TAB.
Used when `whitespace-style' includes the value `space-after-tab'.