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

Issue #2340667 by YesCT, Pedro Lozano, alexpott, martin107: Protect Drupal\Core\Language\Language::id, and use getId().

Issue #2089331 by grom358 | thedavidmeister: [meta] Replace calls to check_plain() with Drupal\Component\Utility\String::checkPlain().

Issue #2246665 by jaredsmith, martin107, YesCT, filijonka, tstoeckler: Typehint with Drupal\Core\Language\LanguageInterface instead Drupal\Core\Language\Language.

Issue #2070369 by herom, bdgreen, Mac_Weber, InternetDevels, sidharthap, JeroenT: Remove all calls to deprecated function language().

Issue #1926344 by jhodgdon, maggo, mdrummond, alexpott, Cottser, dimboz | jenlampton: Consolidate search-result.html.twig and search-results.html.twig.

Revert "Issue #1926344 by jhodgdon, maggo, mdrummond, Cottser, dimboz | jenlampton: Consolidate search-result.html.twig and search-results.html.twig."

This reverts commit c83ff69e.

Issue #1926344 by jhodgdon, maggo, mdrummond, Cottser, dimboz | jenlampton: Consolidate search-result.html.twig and search-results.html.twig.

Issue #1987806 by kim.pepper, disasm, vijaycs85, tim.plunkett: Convert search_view() to a new style controller.

Issue #1751194 by Cottser, mikl, effulgentsia, benjifisher: Introduce hook_theme_suggestions_HOOK() and hook_theme_suggestions_HOOK_alter().

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

Issue #2003482 by pwolanin, jhodgdon, kim.pepper, Nick_vh, tim.plunkett, jibran, Berdir, effulgentsia, alexpott: Convert hook_search_info() to plugin system.

Issue #1754246 by webflo, swentel, penyaskito, andypost, alexpott, YesCT, dagmar: Languages should be configuration entities.

Issue #1668866 by ParisLiakos, aspilicious, tim.plunkett, pdrake, g.oechsler, dawehner, Berdir, corvus_ch, damiankloip, disasm, marcingy, neclimdul: Replace drupal_goto() with RedirectResponse.

Issue #1620010 by dawehner, ParisLiakos, plach, jibran: Move LANGUAGE constants to the Language class.

Issue #1898448 by julien, drupalway, podarok, jenlampton, steveoliver, joelpittet, jwilson3, chrisjlee, Cottser | c4rl: Convert search module to Twig.

Issue #1817484 by tomgeekery, kiamlaluno: Fixed The function contains a 'return' statement right at the end of the function.

Using the language_manager wrapper function to return a language whether or not we're in the requet scope

- Patch #1290694 by hefox, tlattimore, c4rl, chx, tim.plunkett, tstoeckler, msonnabaum: provide consistency for attributes and classes arrays provided by template_preprocess().

- Patch #1510686 by cosmicdreams, vasi1186, webflo, disasm: replace remaining references to global () with drupal_container().

Issue #965300 by Gábor Hojtsy, xjm: Change LANGUAGE_NONE to LANGUAGE_NOT_SPECIFIED; add LANGUAGE_NOT_APPLICABLE and LANGUAGE_MULTIPLE.

Issue #1330922 by ericduran, scor: Fixed Drupal 8 HTML 5 page template should use lang not xml:lang.

Issue #22336 by quicksketch, scor, boombatower, and rfay. Move all core Drupal files under a core subdirectory.

Issue #1136130 by pillarsdotnet: Reinstated WATCHDOG_* constants; using PHP equivalents caused issues on Windows.

- Patch #867114 by jhodgdon, mgifford, sun: search results should add lang tag if language of search result differs.

- Patch #827116 by jhodgdon, marvil07: search API is inconsistent in /, and generally needs doc cleanup.

- Patch #497206 by jhodgdon, pwolanin, Island Usurper, YannickD: avoid search conflicts with other forms, use menu API instead of search_get_keys().

#567100 by jhodgdon, pwolanin, ezra-g: Fixed Search module is assuming node is default search even when it's disabled.