Issue #2552799 by heddn, glenshewchuck, Xano, deepakaryan1988, swentel, jordanpagewhite, yched, tim.plunkett: FieldType with no available widget causes Fatal error

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

Issue #2551511 by alexpott, stefan.r, RavindraSingh, pjonckiere, JeroenT, Mariano: Remove SafeMarkup::set() from AllowedTagsXssTrait

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

Issue #2475237 by mkalkbrenner: Method FieldItemList::equals() uses type safe comparison limiting usefulness.

Issue #2297817 by alexpott, pounard, Berdir, yched, Fabianx, plach, mkalkbrenner: Do not attempt field storage write when field content did not change

Issue #2227227 by mpdonadio, amateescu, yched, larowlan, swentel, tstoeckler, fago: FieldTypePluginManager cannot instantiate FieldType plugins, good thing TypedDataManager can instantiate just about anything

Issue #2330121 by plach, effulgentsia, fago: Replace ContentEntityDatabaseStorage::getSchema() with a new EntityTypeListenerInterface implemented by SqlContentEntityStorageSchema.

Issue #2273311 by donquixote, xjm: Fixed FieldDefinitionTestBase::getNamespacePath() breaks with PSR-4.

Issue #2257769 by tstoeckler | sun: Adding an Entity Reference field in the Field UI throws a PHP notice; fails to add field.