Presentation-related elements DOM elements are now marked as such to help screen readers.
markdown mode: Be more picky about what HTML tags look like to avoid false positives.
findModeByMIME now understands
+xml MIME suffixes.
closebrackets addon: Add support for an
override option to ignore language-specific defaults.
panel addon: Add a
stable option that auto-scrolls the content to keep it in the same place when inserting/removing a panel.