Issue #3278415 by nod_, lauriii, catch, Wim Leers, longwave, xjm, claudiu.cristea: Remove usages of the JavaScript ES6 build step, the build step itself, and associated dev dependencies

Issue #3263823 by Spokje, nod_, kostyashupenko, murilohp, adityasingh, pooja saraah, ravi.shankar, catch: Empty out and deprecate drupal libraries which are related to Internet Explorer 11 polyfills in 10.0.x for removal in 11.0.0

Revert "Issue #3263823 by Spokje, nod_, kostyashupenko, murilohp, adityasingh, pooja saraah, ravi.shankar: Empty out and deprecate drupal libraries which are related to Internet Explorer 11 polyfills in 10.0.x for removal in 11.0.0"

This reverts commit 99059eda.

Issue #3263823 by Spokje, nod_, kostyashupenko, murilohp, adityasingh, pooja saraah, ravi.shankar: Empty out and deprecate drupal libraries which are related to Internet Explorer 11 polyfills in 10.0.x for removal in 11.0.0

Revert "Issue #3238501 by kostyashupenko, Spokje, mherchel, nod_, longwave, lauriii, bnjmnm: Remove Internet Explorer 11 polyfills"

This reverts commit 145d7286.

Issue #3238501 by kostyashupenko, Spokje, mherchel, nod_, longwave, lauriii, bnjmnm: Remove Internet Explorer 11 polyfills

Issue #3231364 by Wim Leers, lauriii, bnjmnm, webchick, xjm, tim.plunkett, larowlan, Luke.Leber, catch, effulgentsia, longwave, gabesullice, caldenjacobs, Reinmar, anand.toshniwal93, Shoshana Mayden, zrpnr, yash.rode, nod_, rkoller, antojose, johnwebdev: Add CKEditor 5 module to Drupal core

Issue #2591827 by longwave, neclimdul, elachlan, daffie: Add YAML linting to core coding standards checks

Issue #3191692 by mherchel, Gauravmahlawat, BhumikaVarshney, bnjmnm, katannshaw: Have secondary menus close on blur

Issue #3108402 by lauriii, bnjmnm, FezVrasta, Wim Leers, mradcliffe, gisle: Update to Popper.js to 2.0.0

Issue #2974553 by Mixologic, justafish, drpal, dawehner: Nightwatch testing fails to save console logs for some tests

Issue #2869825 by justafish, dawehner, alexpott, martin107, jibran, Lendude, Mixologic, michielnugter, droplet, drpal, lauriii, effulgentsia, mglaman: Leverage JS for JS testing (using nightwatch)

Issue #2889600 by droplet, drpal, Gábor Hojtsy, effulgentsia, Wim Leers: [regression] Restore \LocaleJavascriptTranslationTest test coverage and keep testing processed JS file

Issue #2815077 by drpal, mradcliffe, effulgentsia, mpdonadio, nod_, droplet, alexpott, nedjo, tizzo, David_Rothstein, pfrenssen: Adopt airbnb javascript style guide v13 as new baseline javascript coding standards for Drupal 8 core and contrib