Issue #2873696 by nvexler, wengerk, gido, Jo Fitzgerald, xjm: Add @internal to core classes, methods, properties to Form Classes

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

Issue #1392754 by tss, justAChris, jhodgdon: Comply with new documentation standards for @file for namespaced class files

Issue #2420737 by rodrigoaguilera, Pere Orga, Gábor Hojtsy, maxocub, jhodgdon, penyaskito, plach, danigrrl: Differences in dynamic language names are confusing in views, content, etc

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

Issue #2422685 by balagan: Language negotiation configuration page titles inconsistent, should not even mention "negotiation"

Issue #2408977 by geertvd: Fatal error: Cannot access protected property Drupal\block\Entity\Block::$id

Issue #2392319 by alexpott, effulgentsia: Config objects (but not config entities) should by default be immutable

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

Issue #1182850 by xjm, Stefan Lehmann, jmcintyre, Bojhan: Remove full stops at the end of checkbox options.

Issue #1976158 by Berdir | msonnabaum: Rename entity storage/list/form/render "controllers" to handlers.

Issue #2203407 by nod_, sun: Replace #attached library array values with provider-namespaced strings.

Issue #2102477 by alexpott: Convert remainder of language negotiation settings to configuration system.

Issue #1862202 by plach, Berdir, katbailey, ParisLiakos, alexpott, chx, sun, larowlan, Gábor Hojtsy, cosmicdreams, vijaycs85, YesCT, penyaskito, andypost, Albert Volkman, joelpitett: Objectify the language system.

Issue #2086485 by brianV, jibran, pwolanin, disasm: Convert language_negotiation_configure_form() to the new form interface.