Issue #2846379 by alexpott, esolitos, casey: Processing paths in LanguageNegotiationUserAdmin causes 404s while accessing private files

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

Issue #2509300 by dawehner, catch, larowlan: Path alias UI allows node/1 and /node/1 as system path then fatals

Issue #1392754 by tss, justAChris, jhodgdon: Comply with new documentation standards for @file for namespaced class files

Issue #1910318 by katbailey: Make path resolution the responsibility of a series of PathProcessor classes, rather than one PathSubscriber class.