The class is org.activiti.explorer.ui.process.ProcessInstancePage (parent of MyProcessInstancesPage),
currently only name is set:
processInstanceTable.addGeneratedColumn("icon", new ThemeImageColumnGenerator(Images.PROCESS_22));
processInstanceTable.setColumnWidth("icon", 22);
processInstanceTable.addContainerProperty("name", String.class, null);
processInstanceTable.setColumnHeaderMode(Table.COLUMN_HEADER_MODE_HIDDEN);
Support for process instance name expression is tricky: the name is persisted before any variables are added … and as such there is little to evaluate from. But it's doable with a bit of refactoring.