Issue #3222251 by bbrala, longwave: [November 8, 2021] Replace all isset constructs with the null coalescing operator

Issue #2849669 by alexpott, pwolanin, Munavijayalakshmi, dawehner: Fix \Drupal\Component\Utility\Unicode() because of the Symfony mbstring polyfill

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 #2600672 by alexpott, dawehner: Core MarkupInterface implementations used in Twig templates should implement \Countable

Issue #2578377 by YesCT, jhodgdon, Gábor Hojtsy, alexpott, herom, xjm: Make translatable docs consolidated and better for developers

Issue #2570285 by mr.baileys, cpj, stefan.r, alexpott, nlisgo, joelpittet, Aki Tendo, borisson_, chx, dawehner, s_leu, Berdir: Make sure TranslatableMarkup accepts string values only

Issue #2576533 by alexpott, stefan.r, Wim Leers, dawehner, xjm, effulgentsia, catch: Rename SafeStringInterface to MarkupInterface and move related classes

Issue #2570431 by stefan.r, YesCT, David_Rothstein, xjm, catch, effulgentsia, Heine, dawehner, plach, lauriii, alexpott, joelpittet: Document that certain (non-"href") attribute values in t() and SafeMarkup::format() are not supported and may be insecure

Revert "Issue #2570431 by stefan.r, YesCT, David_Rothstein, xjm, catch, effulgentsia, Heine, dawehner, plach, lauriii, alexpott, joelpittet: Document that certain (non-"href") attribute values in t() and SafeMarkup::format() are not supported and may be insecure"

This reverts commit 4d8e0102.

Issue #2570431 by stefan.r, YesCT, David_Rothstein, xjm, catch, effulgentsia, Heine, dawehner, plach, lauriii, alexpott, joelpittet: Document that certain (non-"href") attribute values in t() and SafeMarkup::format() are not supported and may be insecure

Issue #2559971 by stefan.r, alexpott, lauriii, nlisgo, plach, dawehner: Make SafeMarkup::format() return a safe string object to remove reliance on a static, unpredictable safe list

Issue #2509218 by plach, stefan.r, pwolanin, effulgentsia, dawehner, jhedstrom, almaudoh, Wim Leers, subhojit777, iMiksu, alexpott, catch, xjm, lauriii, joelpittet, Cottser: Ensure that SafeString objects can be used in non-HTML contexts

Issue #2569069 by stefan.r, mr.baileys, alexpott, lauriii: Replace TranslationWrapper with TranslatableString and deprecate TranslationWrapper

Issue #2557113 by stefan.r, alexpott, dawehner, joelpittet, cilefen, lauriii, plach, catch, chx, xjm: Make t() return a TranslationWrapper object to remove reliance on a static, unpredictable safe list

Issue #2562487 by stefan.r, chx, tim.plunkett, dawehner, alexpott: Get better error reporting from __toString

Issue #2559969 by alexpott: Make SafeStringInterface extend \JsonSerializable so we don't have to do so much string casting

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 #2506581 by alexpott, Wim Leers, Fabianx, xjm, joelpittet, Cottser, dawehner: Remove SafeMarkup::set() from Renderer::doRender

Issue #2212069 by Gábor Hojtsy, pjonckiere, rteijeiro, cilefen: Non-English Drupal sites get default configuration in English, edited in English, originals not actually used if translated

Issue #2244447 by alexpott, sun, Berdir: Translation of low-level info/annotations leads to circular dependencies.