Issue #2665992 by alexpott, klausi, heykarthikwithu, xjm, tstoeckler: @file is not required for classes, interfaces and traits

Issue #2551907 by Wim Leers, dawehner: Follow-up for #2483183: make the Breadcrumb value object use composition instead of inheritance

Issue #2483183 by lauriii, martin107, Wim Leers, tim.plunkett, moshe weitzman, bfr, Fabianx, dawehner: Make breadcrumb block cacheable