Issue #2234439 by jhodgdon, cosmicdreams, xjm: Add a section for the plugin system to the API doc landing page.

Issue #2261083 by amitgoyal, joshi.rohit100, er.pushpinderrana, aschmoe: Move mention of System Help block from Help module help to System module help

Issue #2124957 by Wim Leers, catch: Replace 'content' cache tag with 'rendered' and use it sparingly.

Issue #2143291 by plach, alexpott, xjm, effulgentsia, pwolanin, swentel | yched: Clarify handling of field translatability.

Issue #1906810 by dawehner, damiankloip, tstoeckler, kgoel, fubhy, jrglasgow, xjm, Gaelan, socketwench: Require type hints for automatic entity upcasting.

Revert "Issue #1906810 by dawehner, damiankloip, tstoeckler, kgoel, fubhy, jrglasgow, xjm, Gaelan, socketwench: Require type hints for automatic entity upcasting."

This reverts commit c9e73f7d.

Issue #2269003 by damiankloip, Berdir: Fixed Unnecessary high memory usage in EntityType::getKeys().

Issue #1906810 by dawehner, damiankloip, tstoeckler, kgoel, fubhy, jrglasgow, xjm, Gaelan, socketwench: Require type hints for automatic entity upcasting.

Revert "Issue #1003788 by stefan.r, Alan D., Josh Waihi, JimmyAx, robhardwick, wiifm, twistor, pwolanin, bzrudi71, bellHead, john_brown: Fixed PostgreSQL: PDOException:Invalid text representation when attempting to load an entity with a string or non-scalar ID."

This reverts commit 4086829b.

Issue #1003788 by stefan.r, Alan D., Josh Waihi, JimmyAx, robhardwick, wiifm, twistor, pwolanin, bzrudi71, bellHead, john_brown: Fixed PostgreSQL: PDOException:Invalid text representation when attempting to load an entity with a string or non-scalar ID.

Issue #2181775 by Ryan Weal, chx | mvc: Fixed SQL idmap broke when using separate mysql users for source and destination.

Isssue #2263047 by joshi.rohit100, amitgoyal: Clean up hook_help example so it complies with hook_help standards

Issue #2285349 by olli: Fixed Fatal error: Call to a member function getType() on a non-object in comment.module on line 951.

Issue #2005434 by alexpott, heddn, andrewmacpherson, swentel: Let 3rd party modules store extra configuration in EntityDisplay.

Issue #2231003 by kay_v, djevans, lokapujya, seiplax | scor: GetPreparedFieldMapping() should return NULL when there are no mappings.

Issue #2284111 by alexpott, Berdir, damiankloip: Fixed Exceptions caught and printed from index.php should not return a 200 status code.

Issue #2278541 by tim.plunkett, kim.pepper, Bojhan, EclipseGc: Refactor block visibility to use condition plugins.

Issue #2039449 by joshi.rohit100, joachim, lokapujya, Jalandhar, paulh, yaworsk: Fix docs for assertField methods in WebTestBase to describe how to skip value checking

Issue #2279617 by thedavidmeister, mgifford: Fixed _filter_url_trim() should use Unicode::truncate().

Issue #2216557 by jhodgdon, mongolito404, Berdir: Fill in @defgroup/topic docs for Testing overview.

Issue #2270815 by vijaycs85, Gábor Hojtsy, nvinayvinay: Make schema testing code available as generic API.

Issue #2246661 by ivanjaros: Some templates are missing 'Default theme implementation ..' statement.