Issue #2349725 by AdamPS, alexpott, hexblot, jonathanshaw, Berdir, larowlan, andypost: Core Mail class prints non-overridable errors on the page

Issue #2286655 by alexpott, attiks, mark_fullmer, nielsonm, Mark Slatinek, quietone, catch, dawehner, aburke626, justafish: Gender neutral language

Issue #2776975 by joelpittet, dawehner, tim.plunkett, xjm, pfrenssen: March 3, 2017: Convert core to array syntax coding standards for Drupal 8.3.x RC phase

Issue #2722265 by willito, kellyimagined, joachim, hussainweb, munizjor, selfuntitled, lisa.ugray, soulsesa, The Sean, kjl16, kurthill4: docs for MailManager::mail() refer to obsolete function user_preferred_langcode()

Issue #2665992 by alexpott, klausi, heykarthikwithu, xjm, tstoeckler: @file is not required for classes, interfaces and traits

Issue #2225427 by ianthomas_uk, martin107, JeroenT, LoMo: Remove remaining uses of deprecated language functions (mostly in object oriented code)

Issue #2358991 by JeroenT, ianthomas_uk, rpayanm, jamesdixon, er.pushpinderrana, Ashok Negi: Remove usage of drupal_mail()

Issue #2301393 by kim.pepper, larowlan: Deprecate all of mail.inc, move drupal_mail to method on Mail plugin manager.