1. accept attribute for file input

    Allows a filter to be defined for what type of files a user may pick with from an `<input type="file">` dialog

  2. Directory selection from file input

    The `webkitdirectory` attribute on the `<input type="file">` element allows entire directory with file contents (and any subdirectories) to be selected.

  3. Multiple file selection

    Allows users to select multiple files in the file picker.

  4. htmlinputelement api: files

  5. htmlinputelement api: showpicker: `file` input

  6. xrinputsource api: profiles

  7. html element: input: `type="file"`