Issue #3367151 by marvil07, Anchal_gupta, xjm, smustgrave, larowlan, longwave, dpi: Docs on return type on two media constraints are misleading

(cherry picked from commit 27c6d955)

Issue #3405798 by alexpott, bircher: Config deleted during import does not have correct initial values set

(cherry picked from commit cf5e2c17)

Issue #3343913 by _shY, smustgrave, catch, xjm, quietone: Add comments explaining performance improvement in TypedData

(cherry picked from commit efecede1)

(cherry picked from commit 9cb09532)

Issue #3181013 by Driskell, alexpott, ericgsmith, Pan Lee, smustgrave, Kristen Pol, mxr576: Faulty permanent config cache has been set to the cache backend on failed sql server connection

(cherry picked from commit 201fd312)

Issue #3391355 by sebish, dpi, smustgrave: \Drupal\Core\Config\StorageInterface::read is typehinted as possibly returning bool, but never returns true

(cherry picked from commit d6f1a5a4)

(cherry picked from commit 6dfc9250)

(cherry picked from commit cd9dd266)

Issue #3390693 by mikelutz, smustgrave: MigrationPluginManager::ExpandPluginIds can lose derivative plugins under certain circumstances

(cherry picked from commit d5d6431e)

Issue #3402548 by alexpott, mikelutz, el7cosmos: YamlFileLoaderTest fails if you have PECL yaml installed

(cherry picked from commit aac47f0d)
(cherry picked from commit bea5ccb1)

Issue #3401764 by BramDriesen, xjm, smustgrave: Replace CollegeHumor URLs and logic in core test cases

Revert "Issue #3383131 by WalkingDexter, xjm, allisonherodevs, ashley_herodev, pradhumanjain2311, smustgrave, marcoliver, lauriii: Entity autocomplete form element ignores entities with label "0""

This reverts commit 18732679.

Issue #3383131 by WalkingDexter, xjm, allisonherodevs, ashley_herodev, pradhumanjain2311, smustgrave, marcoliver, lauriii: Entity autocomplete form element ignores entities with label "0"

(cherry picked from commit 68dfec3c)

Issue #3398400 by pradhumanjain2311, joachim, smustgrave: Clean up repeated method calls in ValidReferenceConstraintValidator

(cherry picked from commit 42c2676d)

(cherry picked from commit 9ef77100)

(cherry picked from commit c304b092)

(cherry picked from commit 35cfa709)

Issue #3377310 by catch, joelpittet, mark_fullmer, smustgrave, TrevorBradley, bkosborne, MWaters, cilefen, capellic: 400 exceptions result from requests for old asset paths which are missing the "theme" query string, possibly from cached pages

(cherry picked from commit 96695551)

(cherry picked from commit 93eb2340)

(cherry picked from commit 5e2dcabf)

Issue #3400485 by googletorp, nod_: LibraryDependencyResolver::getMinimalRepresentativeSubset() calculates dependencies incorrectly

(cherry picked from commit c0895d57)

Issue #3277238 by lauriii, xjm, plopesc, quietone, andregp, Berdir, smustgrave, hmendes, joachim, alexpott, fjgarlin: Fix \Drupal\taxonomy\Entity\Term::getName() to conform to the interface

(cherry picked from commit bd38a5a1)

Issue #3195583 by smokris, smustgrave, mohit.bansal623, xjm, quietone: Fix warning when RSS feed includes markup with an empty srcset attribute

Issue #3015369 by quietone, mikelutz, xjm: Fix MigrateTestBase::executeMigrations() to execute migrations in dependency order

(cherry picked from commit 31911458)

Issue #3383692 by Murz, xjm, smustgrave: Document that NULL is an allowed return value for EntityRepositoryInterface::getTranslationFromContext()

(cherry picked from commit 731c7344)

Issue #3400045 by kristiaanvandeneynde, lauriii, moshe weitzman, xjm: Offering to co-maintain the User subsystem

(cherry picked from commit d7c2ce4c)

Issue #3399685 by poker10, greggles, BramDriesen: Remove Core version from install.php when the site already is installed - Information Disclosure - Leaking version information

(cherry picked from commit 4c95ce55)

Issue #3393955 by quietone, xjm, smustgrave: Correct $suggestions documentation in hook_theme_suggestions_alter()

(cherry picked from commit c85f28b7)

(cherry picked from commit 815a709f)

(cherry picked from commit 8c01b91e)

Issue #3385811 by vbouchet: ContentTranslationUntranslatableFieldsTest should use API to set up language

(cherry picked from commit 13cf026d)

(cherry picked from commit 7a84619f)

Issue #3374537 by camoa, Utkarsh_33, TY4DVenom, Gauravvvv, Indrapatil, narendraR, Harish1688: PostCSS layout helpers inconsistency

(cherry picked from commit 418e5a48)

Issue #3355603 by roshni27, joachim, Ranjit1032002, quietone: Docs for ImageFieldCreationTrait and FileFieldCreationTrait are misleading

(cherry picked from commit 4494b0a4)

(cherry picked from commit 066dc5c8)

(cherry picked from commit b498f70e)

Issue #2960381 by roshni27, joachim, apaderno, smustgrave: Docs for FactoryInterface::createInstance() and MapperInterface::getInstance() are too similar and need more detail