Issue #2571499 by benjy, mikeryan, phenaproxima: idMap source and destination id filtering requires keys

Issue #2361093 by mikeryan, dawehner, Devin Carlson, benjy, phenaproxima: Add a rollback functionality to migrate

Issue #2572599 by stefan.r, dawehner, pwolanin, amateescu: Replace !placeholder with @placeholder in a few remaining places

Issue #2568775 by dawehner, lauriii, alexpott, joelpittet, xjm: Replace remaining !placeholder for Non-URL HTML outputs only for $e->getMessage()

Issue #2568793 by joelpittet, alexpott, Cottser, klausi: Replace remaining !placeholder for Non-URL HTML when format_size() is involved

Issue #2559571 by mikeryan, benjy, phenaproxima, quietone: Handle MigrateException consistently during import

Issue #2503999 by neclimdul, mikeryan, Berdir, catch, andypost: Large volume entity migrations run out of memory

Issue #2501319 by joelpittet, cwells, stefan.r, YesCT, nlisgo, Cottser, cmanalansan, dawehner, xjm, alexpott, josephdpurcell: Remove SafeMarkup::set() in Error::renderExceptionSafe() and _drupal_log_error() and improve backtrace formatting consistency in _drupal_log_error(), Error::renderExceptionSafe(), and DefaultExceptionSubscriber::onHtml()

Issue #2545632 by neclimdul, hussainweb, mikeryan, phenaproxima, benjy: Revert removal of memory reclamation in migrate system

Issue #2535458 by mikeryan, benjy, phenaproxima, EclipseGc, dawehner: Dispatch events at key points during migration

Issue #2491155 by mikeburrelljr, Mac_Weber, opdavies: Update drupal.org and kernel.org URLs in core modules (Follow-up to 2489912)

Issue #2321609 by benjy, dawehner: Fixed Provide a helpful message in case requirements are not met.

Issue #2314289 by benjy: Track result of migrations and use it to properly define migrate_dependencies.

Issue #2079797 by ParisLiakos, Xano, amateescu, tim.plunkett: Provide a trait for $this->t() and $this->formatPlural().

Issue #2213451 by andypost, bdone, benjy, penyaskito, chx, claudiu.cristea, damiankloip, gregboggs, InternetDevels, jessehs, jhedstrom, marvil07, mikeryan, pcambra, Xano, YesCT: Update Migrate API in core

Migrate in core #2125717 by mikeryan, chx, marvil07, bdone, jessehs, mpgeek, BTMash, fastangel, mongolito404, Moshe Weitzman, eliza411, YesCT, dawehner, cosmicdreams