Issue #3089697 by alexpott, swentel: Regression due to File::setValidationRequired in _file_save_upload_single()

Issue #3088447 by Mile23, heddn, Krzysztof Domański: BuildTestBase->standUpServer always starts new server

Issue #3075645 by chr.fritsch, maacl, super_romeo, volkerk, alexpott: temporary://update-cache-60b12ec6 is not a directory. in FileSystem->scanDirectory()

Issue #3085062 by jibran, amateescu, larowlan, xjm, Berdir: Declare a conflict on pathauto versions that aren't compatible with 8.8.0

Issue #3088853 by alexpott, mondrake: Require typo3/phar-stream-wrapper ^3.1.3 and pear/archive_tar ^1.4.8 in order to support PHP 7.4

Issue #2905429 by zrpnr, tim.plunkett, Wim Leers, Jacine: Library definitions containing only dependencies should be valid

Issue #3089168 by phenaproxima, bnjmnm: Remove or reduce representational CSS classes in all Media Library tests

Issue #3088369 by mikelutz, alexpott, Berdir, Gábor Hojtsy, andypost, martin107, greg.1.anderson, dawehner, jibran, Wim Leers, Mile23, catch: Update Drupal 9 to Symfony 4.4-dev

Issue #3088681 by phenaproxima, seanB, bnjmnm, lauriii: Make MediaLibraryTest less dependent on representational CSS selectors

Issue #3088448 by alexpott, greg.1.anderson, Mixologic, Mile23: Remove bin/composer from composer.lock file

Issue #3067251 by zrpnr, catch, lauriii, Wim Leers, xjm, mikelutz, dww, tedbow: Deprecate unused jQuery UI components in favour of a suite of contrib modules

Issue #3079791 by mikelutz, shaal, Wim Leers, hussainweb, xjm, catch, Charlie ChX Negyesi, Mixologic, Gábor Hojtsy, heddn, amateescu: Bump Drupal's minimum PHP version to 7.2 as soon as 9.0.x is branched (a higher version may be required later)

Issue #3067085 by huzooka, lauriii, bnjmnm, tim.plunkett, phenaproxima: Views top dropbutton breaks when editing a view

Issue #3074267 by finnsky, bnjmnm, Wim Leers, zrpnr, lauriii, xjm, catch, droplet, justafish, FezVrasta: Replace jQuery UI position() with PopperJS

Issue #3080259 by gabesullice, alexpott, Wim Leers: Links with different target attributes are improperly merged

Issue #3088135 by alexpott, mikelutz, Wim Leers, Berdir, heddn: TestSiteApplicationTest::testInstallInDifferentLanguage requires localize.drupal.org

Issue #3067386 by tim.plunkett, effulgentsia, bnjmnm, lauriii, Wim Leers, huzooka, xjm: AJAX rebuild of Views UI form re-renders parts of the form without using Form API, so additional hooks are needed in lieu of hook_form_view_edit_form_alter()

Issue #2631202 by tedbow, Mile23, EclipseGc, dawehner, larowlan, tim.plunkett, catch, alexpott, xjm, neclimdul, cilefen, kreynen, StephanieFuda: Doctrine no longer supports SimpleAnnotationReader, incorporate a solution into core

Issue #3088127 by alexpott, Berdir, Wim Leers: Fix FileTransferAuthorizeFormTest and UpdateUploadTest on 9.0.x

Issue #3087991 by catch, jibran: Drupal\Tests\system\Functional\Update\UpdatePathTestBaseFilledTest::testUpdateHookN Failed asserting that 8000 matches expected 8001

Issue #2966607 by Wim Leers, Berdir, claudiu.cristea, dww, Fabianx, effulgentsia, bendev, mondrake, Grayle, neclimdul, markgifford, larowlan: Invalidating 'node_list' and other broad cache tags early in a transaction severely increases lock wait time and probability of deadlock

Issue #3088012 by alexpott, mikelutz, Wim Leers, Berdir: InstallerExistingConfigTest shouldn't download translations from l.d.o

Issue #3072702 followup: Core extensions should not need to specify the new core_version_requirement in *.info.yml files so that 9.0.x can be installed

Issue #3072702 by alexpott, Wim Leers, mikelutz, xjm, catch, Berdir, tedbow, webchick, shaal, Mixologic, heddn: Core extensions should not need to specify the new core_version_requirement in *.info.yml files so that 9.0.x can be installed

Issue #2174633 by colan, mikeker, Lendude, Pancho, Jo Fitzgerald, tim.plunkett, andypost, anya_m, botanic_spark, amateescu, realityloop, tvhung, lokapujya, jhedstrom, rensingh99, dww, Munavijayalakshmi, david.gil, jlbellido, visabhishek, druprad, le72, larowlan, kenton.r, jonathanshaw, Damien Tournoud, mpp, alexpott, dawehner, nicholas.alipaz, TrevorBradley, jp.stacey, Berdir: View output is not used for entityreference options

Issue #3087496 by jhodgdon, andypost, Amber Himes Matz: Change prefixes of Help Topics machine names to help and make sure APIs are marked @internal