Issue #2758897 by Wim Leers, damiankloip, larowlan: Move rest module's "link manager" services to serialization module

Issue #2719695 by alexpott, Mile23: Fix 'Drupal.Classes.ClassDeclaration.CloseBraceAfterBody' coding standard

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

Issue #2423951 by effulgentsia, joelpittet, dawehner, klausi: Document each use of base: in rest.module

Issue #2364157 by mpdonadio, dawehner, martin107, Berdir, pcambra, naveenvalecha, tim.plunkett: Replace most existing _url calls with Url objects

Issue #2355977 by larowlan, dashaforbes: Fixed Code references RelationLinkManagerInterface::getRelationInternalIds but no such method.

Issue #2343661 by larowlan, tim.plunkett | xjm: Rename l() to _l() and url() to _url(), and document replacements.

Issue #2100343 by Berdir, fago, martin107, visabhishek, sriharsha.uppuluri, Yorirou: Remove 'fieldable' key in entity definitions in favour of 'field_ui_base_route'.

Issue #2340123 by Wim Leers: Setting cache tags can be tricky: use strings instead of nested arrays to improve DX.

Issue #2169447 by damiankloip, sun, longwave: DX: Supply CacheBackendInterface::CACHE_PERMANENT as Cache::PERMANENT.

Issue #1953408 by swentel, aspilicious, andypost, yched: Remove ArrayAccess BC layer from field config entities.

Issue #1497374 by yched, chx, amateescu, plach, Damien Tournoud, fago, swentel: Switch from Field-based storage to Entity-based storage.