XDG Extended Attribute spec support

XDG Extended Attributes guidelines include metadata about files that is supported on the file system level. Many programs attach this metadata to downloaded or produced files, and it would seem an essential feature for a file manager to provide a way to view and edit this metadata. In particular, these xattrs are of high relevance:

    user.xdg.comment: supported by Dolphin and other file managers.
    user.xdg.origin.url: for files downloaded from a url.
    user.xdg.robots.index: "true" if a file is included in indexing, "false" otherwise
    user.xdg.robots.backup: "true" if a file is included in backup, "false" otherwise
    user.xdg.language
    user.xdg.creator
    user.xdg.publisher
    user.xdg.origin.email.subject
    user.xdg.origin.email.from
    user.xdg.origin.email.message-id