Issue #3416522 by catch, alexpott, longwave, phenaproxima, nicxvan, wim leers, smustgrave, larowlan, berdir, godotislate, dww: Add the ability to install multiple modules and only do a single container rebuild to ModuleInstaller

Issue #3483299 by tstoeckler, mstrelan, nicxvan: Add void return type to all preprocess hook implementations

Issue #3483599 by nicxvan, ghost of drupal past, catch, longwave, fabianx: Convert all procedural hook implementations to Hook classes

Issue #3465602 by catch, quietone, smustgrave: Order tests by number of public methods to optimize gitlab job times

Issue #3421418 by mstrelan, Spokje, xjm, mondrake, longwave, acbramley: Add void return typehints to all test methods

Issue #3353210 by mondrake, PrabuEla, Spokje: [PHPUnit 10] @dataProvider methods must be declared static and public

Issue #2441373 by twistor, vsujeetkumar, marvil07, eporama, daffie, joseph.olstad, alvar0hurtad0, jibran, longwave, joelpittet, smustgrave, alexpott: Upgrade tests to HTML5

Issue #3386458 by catch, quietone, alexpott, larowlan: Add GenericModuleTestBase and use it to test general module things

Issue #3325557 by longwave, mondrake, kim.pepper: Enable more service autowiring by adding interface aliases to core modules

Issue #3273317 by clayfreeman, larowlan, tim.plunkett, danflanagan8: Add 'in_preview' variable to block and layout templates

Issue #3222251 by bbrala, longwave: [November 8, 2021] Replace all isset constructs with the null coalescing operator

Issue #3133162 by jungle, ravi.shankar, Deepak Goyal, Neslee Canil Pinto, anmolgoyal74, xjm, Kristen Pol: Replace the start verb Test with Tests in method comments of tests

Issue #3131343 by mondrake, dww, jungle: Replace assertions involving calls to in_array() with assertContains()/assertNotContains()

Issue #2822382 by voleger, pfrenssen, erozqba, jungle, RytoEX, borisson_, jofitz, shashikant_chauhan, sidharthap, dawehner, xjm, kiamlaluno, catch, daffie, klausi: Make every $modules property protected on classes extending BrowserTestBase and KernelTestBase

Issue #3107732 by mondrake, longwave, swatichouhan012, salah1, xjm, catch, alexpott, Berdir: Between April 13 and April 17, 2020: Add return typehints to setUp/tearDown methods in concrete test classes

Issue #3106666 by catch, jungle, xjm, alexpott, tim.plunkett, Berdir: Remove post updates added prior to 8.8.0

Issue #3087644 by jibran, Berdir, alexpott, longwave, Wim Leers, amateescu, catch, xjm, larowlan, dpi, quietone: Remove Drupal 8 updates up to and including 88**

Revert "Issue #3087644 by jibran, Berdir, alexpott, longwave, Wim Leers, amateescu, catch, larowlan, dpi, quietone: Remove Drupal 8 updates up to and including 88**"

This reverts commit 136f0550.

Issue #3087644 by jibran, Berdir, alexpott, longwave, Wim Leers, amateescu, catch, larowlan, dpi, quietone: Remove Drupal 8 updates up to and including 88**

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 #2904550 by tim.plunkett, Sam152, jwilson3, neclimdul, eelkeblok, amateescu, DuaelFr, K3vin_nl, alexpott, tedbow, andypost: PluginDependencyTrait::calculatePluginDependencies() does not handle theme provided plugins

Issue #2938132 by tedbow, tim.plunkett, xjm, EclipseGc, AaronMcHale, alexpott, DyanneNova: Ship layouts that make sense with Layout Builder's concept of sections

Revert "Issue #2822382 by voleger, pfrenssen, erozqba, RytoEX, borisson_, sidharthap, Jo Fitzgerald, shashikant_chauhan: Make every  property protected on classes extending BrowserTestBase and KernelTestBase"

This reverts commit 69501f30.

Issue #2822382 by voleger, pfrenssen, erozqba, RytoEX, borisson_, sidharthap, Jo Fitzgerald, shashikant_chauhan: Make every  property protected on classes extending BrowserTestBase and KernelTestBase

Issue #2861840 by tim.plunkett, lauriii: Preprocess functions are not merged when a module registers a theme hook for a theme-provided template

Issue #2660124 by tim.plunkett, samuel.mortenson, phenaproxima, tstoeckler, yoroy, dead_arm, xjm, Manuel Garcia, EclipseGc, larowlan, DyanneNova, tedbow: Dynamically build layout icons based on well formed config

Issue #2834025 by tim.plunkett, Manuel Garcia, swentel, japerry: Mark Layout Discovery as a stable module

Issue #2885877 by tim.plunkett, EclipseGc: Add support for per-region attributes to Layout Templates

Issue #2852608 by Manuel Garcia, DyanneNova, markconroy, tim.plunkett, joelpittet, DickJohnson, Scorpid: Review layout CSS and markup

Issue #2857410 by tim.plunkett, DamienMcKenna: Adding a page-level #prefix or #suffix causes it to be output twice on one-col layout