bootswatch/bower_components/bootstrap/less/mixins/reset-filter.less

Bootswatch is a collection of themes for Bootstrap.

// Reset filters for IE
//
// When you need to remove a gradient background, do not forget to use this to reset
// the IE filter for IE9 and below.

.reset-filter() {
  filter: e(%("progid:DXImageTransform.Microsoft.gradient(enabled = false)"));
}