Issue #3335768 by Berdir, andypost, smustgrave, catch: Manually clear cache keys from plugin managers with finite variations instead of using cache tags

Issue #3104307 by Berdir, longwave, Gábor Hojtsy, Wim Leers, alexpott, andypost: Remove  BC layers in various Drupal\Core components

Issue #2722237 by webflo, dawehner, borisson_, drunken monkey, Wim Leers: "Local actions" block doesn't take cache data of route access information into account

Issue #2912169 by alexpott, tobiberlin, Berdir, dawehner, grahamC: Inject the argument resolver into HttpKernel::__construct

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 #2624594 by pwolanin, lauriii, Xano: Local action plugins do not have any way to provide cacheability metadata

Issue #507488 by lauriii, mdrummond, Wim Leers, Manuel Garcia, pwolanin, davidhernandez, chx, jibran, andypost, dawehner, Xano, tuutti, Gábor Hojtsy, LewisNyman, maximiliam, eiriksm, borisson_, bill richardson, Fabianx, joelpittet, Jeff Burnz, xjm, webchick, Bojhan, EclipseGc, emma.maria, tim.plunkett: Convert page elements (local tasks, actions) into blocks

Issue #2338081 by pwolanin, dawehner, effulgentsia, kgoel, vijaycs85, mpdonadio, chx, brandon.holtsclaw, alexpott, Gábor Hojtsy, Fabianx, catch, YesCT, JvE: Local Tasks, Actions, and Contextual links mark strings from derivatives (or alter hooks) as safe and translated

Issue #2422815 by Xano, fgm, tim.plunkett, dawehner: Don't initialize the discovery object in plugin managers, unless needed

Issue #2294157 by tim.plunkett, dawehner: Switch getOptions() and getRouteParameters() within LocalActionInterface and LocalTaskInterface to use RouteMatch

Issue #2347465 by tim.plunkett, dawehner, cilefen: Convert all instances of #type link/links to convert to use routes.

Issue #2340123 by Wim Leers: Setting cache tags can be tricky: use strings instead of nested arrays to improve DX.

Issue #2318281 by tim.plunkett, dawehner | kim.pepper: Provide a standard way to check a plugin is an instance of the required interface.

Issue #2310705 by lokeoke, tim.plunkett, dawehner: AccessManager should introduce constants for 'ANY' / 'ALL'.

Issue #2053153 by tim.plunkett, dawehner, damiankloip, aspilicious: Allow contrib modules to provide plugins on behalf of optional modules.

Issue #2048223 by dawehner, ParisLiakos, herom, fubhy, damiankloip, vijaycs85, joelpittet, tim.plunkett: Add $account argument to AccessCheckInterface::access() method and use the current_user() service.

Issue #2077473 by dawehner, damiankloip, pwolanin: Replace local action plugin discovery with YamlDiscovery and handle routes with parameters.

Revert "Issue #2002162 by klausi, eugene.ilyin: Convert form validation of users to entity validation."

This reverts commit 5b41b6f8.

Issue #2031473 by pwolanin, fubhy, dawehner, tim.plunkett: Convert menu local actions to plugins so that we can generate dynamic titles and paths.