For clarity, only the Silver Star is missing the full service diner car during the "experiment" which has been extended through the end of April. The Silver Meteor still has a regular dining car.
Neither of the trains, Star or Meteor, have dining car service according to the Amtrak reservation website. Both show the "red" triangle which states, "Silver Star Trains 91 & 92 - Dining Car Temporarily Removed, Resulting in Lower Cost Sleeping Accommodations Option Effective through April 30, 2016".
What meal service is thus provided?
The text you quoted specifically states the Silver Star 91 & 92 does not have the dining car.
Following the links from the red triangle, the complete explanation states "Passengers will continue to have the option of choosing traditional Dining Car service aboard the Silver Meteor (Trains 97 & 98), which operates along much of the Silver Star route. Dining Car meals aboard the Silver Meteor are included in the Sleeping Car upgrade charge."
They presumably included the warning triangle for the Meteor reservation so those deciding between the two trains would be provided the same information for both trains.