Issue #77245 by drpal, tedbow, nod_, phenaproxima, Wim Leers, googletorp, rteijeiro, vineet.osscube, tim.plunkett, idflood, joelpittet, pk188, lauriii, BarisW, lokapujya, chr.fritsch, droplet, andrewmacpherson, dmsmidt, dawehner, alexpott, jessebeach, NickWilde, DuaelFr, Cottser, seutje, samuel.mortenson: Provide a common API for displaying JavaScript messages

Issue #2003570 by aparnakondala123, vineet.osscube, tstoeckler: Fixed Enabling RTL and then changing theme colors moves the hexadecimal # to the right.

Issue #2041625 by vineet.osscube, tim.plunkett, tkoleary: Fixed Add space between file upload and button.

Issue #2041313 by vineet.osscube: Fixed Caching issue causes 'theme not found' error when enabling theme.

Issue #1980338 by vineet.osscube, nick_schuch: Fixed Fatal error: Class 'plugin.manager.block' not found in /core/modules/system/system.module on line 1162.