Issue #352951 by Wim Leers, mfer, mcjim, larowlan, RobLoach, sdboyer, Owen Barton, JohnAlbin: Make JS & CSS Preprocessing Pluggable.

Issue #1833022 by e0ipso, plach, YesCT, kfritsche, penyaskito, vijaycs85, nod_, cam8001: Only display interface language detection options to customize more granularity.

Issue #1974580 by nod_, Wim Leers: Introduce domReady to remove jQuery dependency from drupal.js and clean it up.

Issue #1396892 by larowlan, nick_schuch | quicksketch: Fixed drupal_get_library() may break JavaScript library path by clobbering it with the library version number.

Issue #1875632 by Wim Leers: Fixed Change Drupal JS settings merging behavior: preserve integer keys (allow for array literals in drupalSettings)

Issue #1824778 by vijaycs85, ACF, pcambra, cam8001: Covert css_gzip_compression() and js_gzip_compression() variables to CMI system.

Issue #1269742 by katbailey, beejeebus, pwolanin, g.oechsler, ksenzee: Make path lookup code into an pluggable class.

Issue #1664602 by quicksketch, Wim Leers, sun, webchick, nrussell: Fixed drupal_add_js() defer and async options break when aggregation is enabled (Replace with universal attributes array).

Issue #1798724 by andreiashu, Albert Volkman, alexpott: Convert drupal_js_cache_files() to State system.

Issue #1798724 by andreiashu, Albert Volkman, alexpott: Convert drupal_js_cache_files() to State system.

Issue #1431658 by Albert Volkman, xjm, kid_icarus, ChinggizKhan, rgristroph, connork: Massive API docs cleanup for system tests

Issue #1362974 by droplet, dcam, Jacine, tkrajcar: Remove type='text/javascript' from <script> tags.

Issue #1764634 by tim.plunkett, nod_: Fixed Drupal.settings is only populated if a custom setting is added.

Issue #1737148 by nod_, SebCorbin, larowlan, tim.plunkett, Albert Volkman, nick_schuch, sun: Explicitly declare all JS dependencies, don't use drupal_add_js().

Issue #1669902 by alexpott, aspilicious, sun: Adjust system.performance configuration for new guidelines.

Issue #1711070 by kid_icarus, tim.plunkett, xjm, droplet, zendoodles and cam8001: Convert tests to use ::$modules property instead of parent::setUp($modules).

Issue #1561004 by marcingy, aries, yurtboy, Tor Arne Thune: Many tests still reference locale although they only need language module.