Issue #1947814 by vijaycs85, Gábor Hojtsy, tim.plunkett: Fixed New config entities often save as langcode: und incorrectly.

Issue #1877632 by fago, jhodgdon: Improve comments and clean-up code for EntityNG and the TypedData API.

Issue #1833334 by das-peter, plach, Berdir, fago: EntityNG: integrate a dynamic property data table handling.

Issue #1874300 by Berdir, swentel: Remove $entity_type argument from field.module functions that receive a single $entity.

Issue #1825044 by sun: turn contact form submissions into full-blown Contact Message entities, without storage.

Issue #1238484 by mrfelton, ry5n, aspilicious, Bojhan, Xano, nod_, rootatwc, effulgentsia, chx, sun: Ability to mark the form buttons to be of a specific type (so that they can be styled differently).

Issue #1188388 by plach, peximo, YesCT | Gábor Hojtsy, fago, webchick, Bojhan, podarok, cosmicdreams, Berdir, aspilicious, bforchhammer, penyaskito: Added Entity translation UI in core.

Issue #1696640 by fago, effulgentsia, tim.plunkett, dixon_, plach: Add a uniform Entity Property API.

Issue #1498874 by peximo, plach, Gábor Hojtsy, attiks: Provide language awareness to entity forms (introduce the form language concept).