What is the fine-grained topic of the following text: Dolores Huerta, another Debs, a piercing-eyed Pullman porter (which honestly I first thought was someone peeing in the alley), and even more labor heroes appearing beyond the immediate neighborhood: Harriet Tubman, Frederick Douglass, A Philip Randolph, a young Caesar Chavez, Lucy Parsons, even Debs’ beloved hunting dog Babe. Only return the topic.
Historical labor heroes