Issue #2551453 by LoMo, Ayesh, jaxxed, LinL, madhavvyas, Miraya: Follow-up: Consistently use "email" instead of "e-mail" in Drupal

Issue #2112679 by Berdir, damiankloip, nlisgo, krlucas, lokapujya, m1r1k, piyuesh23, blueminds, stefan.r, subhojit777, dawehner, kerby70, Dustin LeBlanc, znerol, JeroenT, borisson_, scor, amitgoyal, s_leu: getUsername() should return the username getDisplayName() for the formatted user name

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 #2560641 by alexpott, lauriii, Xano, borisson_, ianthomas_uk, olli: Remove all usages SafeMarkup::checkPlain() from render arrays

Revert "Issue #2560641 by alexpott, lauriii, Xano, borisson_, ianthomas_uk: Remove all usages SafeMarkup::checkPlain() from render arrays"

This reverts commit 31007609.

Issue #2560641 by alexpott, lauriii, Xano, borisson_, ianthomas_uk: Remove all usages SafeMarkup::checkPlain() from render arrays

Issue #2463009 by Wim Leers: Introduce CacheableResponseInterface: consolidate ways of setting X-Drupal-Cache-Tags/Contexts headers

Issue #2453341 by Wim Leers: Contact forms don't have necessary cache contexts & tags; flood control should work on validate, not on view

Issue #2444231 by Wim Leers, nlisgo: Fix CacheableInterface so it makes sense (was: "Make Config objects & Entities implement CacheableInterface + add BubbleableMetadata::createFromCacheableObject()")

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

Issue #2407765 by Wim Leers, borisson_: Wherever simple config is used to render output to end user, associate their cache tags

Issue #2225597 by tibbsa, larowlan, akozma: contact.module allows you to send emails to users with no email address - producing an error

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

Issue #950534 by mparker17, mgifford, Mixologic, jbloomfield, erinclerico, theMusician, wmostrey | zirvap: [policy] Consistently use email instead of e-mail in Drupal.

Issue #2110501 by tim.plunkett, pwolanin, tstoeckler: ControllerBase should implement ContainerInjectionInterface like FormBase.

Issue #1938390 by andypost, disasm, jibran, dawehner, ygerasimov, pfrenssen: Convert contact_site_page and contact_person_page to a new-style Controller.

Issue #2089635 by tim.plunkett, disasm, larowlan: Convert non-test non-form page callbacks to routes and controllers.