Issue #2937945 by yo30, kim.pepper, dawehner, voleger, larowlan: Add messenger to ControllerBase and FormBase

Issue #2927563 by tstoeckler, amateescu: Aggregator feed "refresh" field should have a default value

Issue #2903908 by mfernea, martin107: Fix 'Drupal.Commenting.FunctionComment.ParamCommentIndentation' coding standard

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 #2570355 by Sutharsan, stefan.r, kgoel, josephdpurcell, joelpittet, justAChris, dawehner, pfrenssen, pwolanin, David_Rothstein, catch: Replace remaining !placeholder and @placeholder with :placeholder for URLs

Issue #2549791 by alexpott, Wim Leers: Remove SafeMarkup::xssFilter() and provide ability to define #markup escaping strategy and what tags to filter

Issue #2228823 by StryKaizer, ParisLiakos, joshi.rohit100, Nitesh Sethia, Aron Novak, geertvd: Aggregator feed overview misleading text

Issue #2506195 by alexpott, joelpittet, xjm, David_Rothstein, Fabianx, pwolanin: Remove SafeMarkup::set() from Xss::filter()

Issue #2456521 by pjonckiere, mpdonadio, jhodgdon, rteijeiro, David_Rothstein, xjm: Add DateFormatter::formatDiff() as a non-buggy alternative to DateFormatter::formatInterval() when the start and end of the interval are known

Issue #2433599 by Wim Leers: Ensure every (non-views) pager automatically associates a matching cache context

Issue #2350877 by dawehner, Wim Leers, hussainweb: Deprecate/rename drupal_add_feed(), drupal_add_html_head(), drupal_add_html_head_link(), drupal_add_http_header(), and allow to be set declaratively in #attached.

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

Issue #2277103 by tim.plunkett, pwolanin, Wim Leers, dawehner, hotpizzas: Switch Drupal::l() and LinkGenerator to expect a Url object.

Issue #2343651 by xjm, tim.plunkett, Wim Leers, dinarcon, dawehner: Remove most remaining l() calls.

Issue #2261425 by ParisLiakos, alexpott: Streamline aggregator's entities rendering with rest of core.

Issue #2149197 by penyaskito, mikey_p, vijaycs85, herom: Replace format_interval with \Drupal::service('date')->formatInterval().

Issue #2241229 by Wim Leers: Aggregator Feed & Item content entity types, and AggregatorFeedBlock should use cache tags.