Issue #2560783 by stefan.r, joelpittet, lauriii, Cottser, Sutharsan, kgoel, justAChris, Gábor Hojtsy, dawehner, jhodgdon, effulgentsia, xjm, andypost, googletorp: Replace !placeholder with :placeholder for URLs in hook_help() implementations

Issue #2566447 by stefan.r, joelpittet, alexpott, lauriii, dawehner: Cast safe string objects to string or use assertEqual() in some assertIdentical() comparisons

Issue #2424805 by mdrummond, YesCT, vijaycs85, xjm, marcoscano, ifrik, joelpittet, Jelle_S, attiks, lauriii: Toolbar can no longer switch horizontal and vertical -- expects breakpoints ordered from smallest to largest; responsive images need largest to smallest

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

Issue #2422815 by Xano, fgm, tim.plunkett, dawehner: Don't initialize the discovery object in plugin managers, unless needed

Issue #2491155 by mikeburrelljr, Mac_Weber, opdavies: Update drupal.org and kernel.org URLs in core modules (Follow-up to 2489912)

Issue #356399 by dawehner, beejeebus, catch, sidharrell, klausi, nlisgo, Josh Waihi, Berdir, martin107: Optimize the route rebuilding process to rebuild on write

Issue #2260061 by Jelle_S, attiks, Wim Leers, mdrummond, mgifford, holist: Responsive image module does not support sizes/picture polyfill 2.2

Issue #2398847 by kattekrab: Remove reference to Breakpoint_UI module from Breakpoint module help text

Issue #2342439 by pgautam, joshi.rohit100 | webchick: Some test modules/themes missing Testing package assignment in their info files.

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

Issue #2228125 by dawehner: 'base theme' property in theme .info.yml files does not need to be wrapped in quotes

Issue #2260121 by sun: PHPUnit Tests namespace of modules is ambiguous with regular runtime namespace (+ Simpletest tests).

Issue #2318801 by jarsenx, mbrett5062: Breakpoint Module: Fix documentation that refers to enabling/disabling of modules.

Issue #2271529 by attiks, alexpott, Lowell, YesCT, Jelle_S | mdrummond: Move breakpoint settings to theme and module *.breakpoints.yml files at root level.

Issue #697760 by sun: Replace getInfo() in tests with native phpDoc + annotations (following PHPUnit).

Issue #2256679 by alexpott, tim.plunkett: Fixed Use config schema to determine which config entity properties to export regardless of whether they are public or protected.

Issue #2190313 by pfrenssen, Berdir, amateescu, ianthomas_uk: Add $EntityType::load() and loadMultiple() to simplify loading entities.

Issue #2183113 by jhodgdon, effulgentsia, tim.plunkett, herom, larowlan: Update hook_help signature to use route_name instead of path.

Issue #2233787 by alexpott, xjm | tim.plunkett: Move default configuration into extension/config/install to clarify its purpose.

Issue #2226027 by tim.plunkett: ConfigEntityBase::preSave() tries to load the original entity but instead loads itself.

Issue #2080823 by alexpott, swentel, Wim Leers: Create API to discover content or config entities' soft dependencies and use this to present a confirm form on module uninstall.

This reverts commit ae8be3cc.

Issue #2199483 by damiankloip, alexpott: Provide a default config_prefix based on entity type ID and provider.