ORLANDO, Fla. -- Since the killings at Pulse, archivists and curators with the Orange County Regional History Center have collected, catalogued and cared for thousands of touching memorials left in tribute to the Orlando night club, its patrons and the tragedy’s survivors and victims. Among the gatherers, Pam Schwartz, chief curator in 2016 and now the History Center’s executive director, learned to preserve the emotional outpouring, an unusual expertise she has offered to those tasked with archiving grief from sites of the latest gun massacres — Robb Elementary School in Uvalde, Texas; Tops s...