Issue #2052473 by ricky.middaugh, lokapujya, Jalandhar, mgifford, jessebeach, BarisW, falcon03: Add aria-label or aria-describedby attributes to all <nav> elements.

Issue #2013094 by pwieck, Cottser: Remove unnecessary template_preprocess() reference from all Twig files

Issue #1898050 by duellj, Cottser, meeli, dsdart, Fabianx | c4rl: book.module - Convert PHPTemplate templates to Twig.

Issue #1760530 by jenlampton, Albert Volkman, crazyrohila, Risse, justafish, Fabianx: Move all template files provided by core modules and themes into a 'templates' directory inside that module directory.

Nate Lampton authored Oct 30, 2011 and catch committed Nov 01, 2011

Issue #22336 by quicksketch, scor, boombatower, and rfay. Move all core Drupal files under a core subdirectory.

- Patch #999040 by Niklas Fiekas: corrected alternative control structure syntax in theme templates.

- Patch #283723 by pwolanin, sun | eddified, moshe weitzman, Dries, aether, Arancaytar: Added Make menu_tree_output() return renderable output.