Issue #3266568 by mxr576, sourabhjain, quietone: Refactor array_merge() usage in loops as possible for performance

Issue #3164210 by jungle, sylus, Akhildev.cs, dww: Refactor array_merge() usage in loops as possible for performance

Issue #2776975 by joelpittet, dawehner, tim.plunkett, xjm, pfrenssen: March 3, 2017: Convert core to array syntax coding standards for Drupal 8.3.x RC phase

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

Issue #2457887 by prateekMehta, stefan.r, rpayanm, alexpott: Use Utility\SafeMarkup class instead of Utility\String for placeholder(), checkPlain(),format() functions

Issue #2292025 by tim.plunkett: Convert BreadcrumbBuilderInterface applies() and build() to use RouteMatch.

Issue #2079797 by ParisLiakos, Xano, amateescu, tim.plunkett: Provide a trait for $this->t() and $this->formatPlural().

Issue #2031485 by paulh, alarcombe, ghazlewood, kgoel, msonnabaum, jhodgdon: BreadcrumbManager's docblock is a lie.

Issue #2099095 by jibran, tim.plunkett: Create BreadcrumbBuilderBase and remove the boilerplate code from BreadcrumbBuilders.

Issue #2070651 by pwolanin, dawehner, larowlan, tim.plunkett, ParisLiakos: Introduce a path-based breadcrumb builder, remove the one that's based on {menu_links()}.

Issue #1947536 by andypost, donquixote, larowlan, splatio, kim.pepper, alexpott, Crell, tim.plunkett: Convert drupal_get_breadcrumb() and drupal_set_breadcrumb() to a service.