Issue #3328454 by xjm, Bhanu951, jidrone, smustgrave: Replace most strpos() !== FALSE or === FALSE with str_contains()

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

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 #2700661 by anoopjohn: Ensure core compliance to Drupal.Commenting.FunctionComment.ParamCommentIndentation (part 1).

Issue #2665992 by alexpott, klausi, heykarthikwithu, xjm, tstoeckler: @file is not required for classes, interfaces and traits

Issue #2571845 by drupal.ninja03, hussainweb, anil280988, snehi, jhodgdon, GoZ, stefan.r: Links to wikipedia/php.net should be part of the actual t() string so they can be localized

Issue #2572695 by marvin_B8, attiks, pfrenssen, xjm: Fix 'Drupal.ControlStructures.ElseIf' coding standard

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

Issue #2562155 by stefan.r, joelpittet, alexpott: Cast TranslationWrapper objects in config to string during Config::set()/setData()

Issue #2524082 by pfrenssen, Gábor Hojtsy, Wim Leers, Berdir, Fabianx, dawehner, catch: Config overrides should provide cacheability metadata

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 #2040135 by Wim Leers, Berdir: Caches dependent on simple config are only invalidated on form submissions

Issue #2380607 by Berdir, dawehner: Do not call ConfigBase::validateKeys() for data loaded from storage

Issue #2293773 by Gábor Hojtsy, alexpott, effulgentsia, penyaskito, hussainweb: Fixed Field allowed values use dots in key names - not allowed in config.

Issue #2216961 by Gábor Hojtsy, xjm | alexpott: Document Config, ConfigBase, and StorableConfigBase.

Issue #2215413 by Eli-T, alexpott: Split the Config class into StorableConfigBase and ConfigBase. Make ThemeSettings inherit from ConfigBase.