This is a navbox template for U.S. Navy LSM-1-class landing ships medium. Because of the large number of ships of this class, the template has features that help to minimize the size of the template on article pages.
where the optional parameter is the last number ending in "00" before the LSM's hull number (i.e. for LSM-149, use 100; for LSM-539, use 500), the template can show a portion of the links, like this: