On the progress text, the current video quality will have a "+" suffix if there's a higher one available.
Hovering the mouse cursor onto the video quality text will show the current and available video quality IDs and short description.
A "[C]" text may be shown to indicate subtitle availability, and hovering the mouse over it will show the available subtitle languages.
For videos which have 60fps and/or HDR video qualities, the listed available video qualities only includes the highest quality ones. The video player may present a lower video quality depending on the network speed, web browser capability, and user account setting.
Hovering the chapter box will display the previous and/or next chapter titles.
Hovering the mouse over the publication date will show a tooltip containing the complete publication date in local time, considering that YouTube may only shows how long the video was published. If the video was live streamed, it will contain the starting and ending recording time.
For new YouTube layout only.