Issue #1834002 by Gábor Hojtsy: Fixed Delete operations are all over the place. Remove tabs, provide title in routing.

Issue #1981368 by tim.plunkett, Crell, webchick: Convert all routes to 'module_name().foo_bar()' naming convention.

Issue #2068053 by tim.plunkett, larowlan: Fixed Custom block creation form redirect is inconsistent.

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

Issue #1997262 by andypost, nick_schuch, larowlan, tim.plunkett, jibran, chertzog, kim.pepper: Convert custom_block_delete_form() to new form interface.

Issue #1847002 by tim.plunkett, effulgentsia, msonnabaum: Move entity type classes from Drupal$provider\Plugin\Core\Entity to Drupal$provider\Entity.

Issue #2062817 by xjm: Fixed Custom block edit path is incorrect in hook_admin_paths() and the configure path is missing from the .info.

Issue #1983682 by tim.plunkett, h3rj4n, larowlan: Convert applicable custom_block_menu() entries to use _entity_form() in routing.yml.

Issue #1981306 by aspilicious, andypost, pcambra, swentel, amateescu: Drop procedural usage of fields in [a-e] modules.

Issue #1978166 by larowlan, smiletrl, tim.plunkett, effulgentsia: Convert block/add/{%custom_block_type()} to Controller.

Issue #1898038 by jenlampton, joelpittet, duellj, Cottser, Shawn DeArmond, widukind, ezeedub, c4rl: Custom_block().module - Convert theme_ functions to Twig.

Issue #1927608 by EclipseGc, tim.plunkett, effulgentsia: Remove the tight coupling between Block Plugins and Block Entities.

Issue #1987298 by tim.plunkett, quicksketch: Shorten directory structure and PSR-0 namespacing for plugins.

Issue #1946404 by tim.plunkett, amateescu, swentel: Convert forms in field_ui().admin.inc to the new form interface.

Issue #1871696 by tim.plunkett, xjm, sun, msonnabaum, EclipseGc: Convert block instances to configuration entities to resolve architectural issues.

Issue #1535868 by EclipseGc, tim.plunkett, xjm, Jody Lynn, sdboyer, naxoc, tizzo, effulgentsia, dawehner, disasm, beejeebus: Convert all blocks into plugins.