Updated img scope (somehow didn't get changed). Changed ins and del tags to have YYYY-MM-DD and YYYY-MM-DDThh mm ssTZD options.
Updated audio and video outdated notices to be more descriptive, include option for downloading. Changed class names to use a "notice-" prefix, to allow for different types of these sorts of content patterns (notice-js, notice-outdated, etc.).
longdesc lives on! Added it as a suffix for the better-supported aria-describedby attribute for targeting more in-depth descriptive copy elsewhere.