boostrap missing responsive-980px-1199px

responsive-980px-1199px.less

// Responsive: Normal desktops
// --------------------------------------------------

@media (min-width: 980px) and (max-width: 1199px) {

  // Fixed grid
  #grid > .core(@gridColumnWidth980, @gridGutterWidth980);

  // Fluid grid
  #grid > .fluid(@fluidGridColumnWidth980, @fluidGridGutterWidth980);

  // Input grid
  #grid > .input(@gridColumnWidth980, @gridGutterWidth980);

  // No need to reset .thumbnails here since it's the same @gridGutterWidth

}

responsive.less

// Small desktops
@import "responsive-980px-1199px";

variables.less

// basic grid
// 980px-1199px
@gridColumnWidth980:      56px; // Feel free to modify this value !
@gridGutterWidth980:      24px; // Feel free to modify this value !
@gridRowWidth980:         (@gridColumns * @gridColumnWidth980) + (@gridGutterWidth980 * (@gridColumns - 1));

// Fluid grid
// 980px-1199px
@fluidGridColumnWidth980:      percentage(@gridColumnWidth980/@gridRowWidth980);
@fluidGridGutterWidth980:      percentage(@gridGutterWidth980/@gridRowWidth980);