1. :indeterminate CSS pseudo-class

    The `:indeterminate` pseudo-class matches indeterminate checkboxes, indeterminate `<progress>` bars, and radio buttons with no checked button in their radio button group.

  2. CSS writing-mode property

    Property to define whether lines of text are laid out horizontally or vertically and the direction in which blocks progress.

  3. Decorators

    ECMAScript Decorators are an in-progress proposal for extending JavaScript classes. Decorators use a special syntax, prefixed with an `@` symbol and placed immediately before the code being extended.

  4. progress element

    Method of indicating a progress state.

  5. XMLHttpRequest advanced features

    Updated functionality to the original XHR specification including things like file uploads, transfer progress information and the ability to send FormData. Previously known as [XMLHttpRequest Level 2](https://www.w3.org/TR/2012/WD-XMLHttpRequest-20120117/), these features now appear simply in the XMLHttpRequest spec.

  6. applicationcache api: `progress` event

  7. backgroundfetchregistration api: `progress` event

  8. filereader api: `progress` event

  9. htmlmediaelement api: `progress` event

  10. htmlprogresselement api

  11. htmlprogresselement api: labels

  12. htmlprogresselement api: max

  13. htmlprogresselement api: position

  14. htmlprogresselement api: value

  15. progressevent api

  16. progressevent api: lengthcomputable

  17. progressevent api: loaded

  18. progressevent api: `progressevent()` constructor

  19. progressevent api: total

  20. xmlhttprequestupload api: `progress` event

  21. xmlhttprequest api: `progress` event

  22. css property: -webkit-column-progression

  23. css property: appearance: progress-bar

  24. css property: cursor: progress

  25. css property: direction: control direction of vertical range sliders, meters, and progress bars

  26. css selector: `::-moz-progress-bar`

  27. css selector: `::-moz-range-progress`

  28. css selector: `::-webkit-progress-bar`

  29. css selector: `::-webkit-progress-inner-element`

  30. css selector: `::-webkit-progress-value`

  31. css selector: `:indeterminate`: applies to `<progress>` elements

  32. html element: progress: max

  33. html element: progress: value