Examples:
- Dialogs
- Toast
- Mobile full and partial page displays
- Process dialogs
- Popups (see T154921: Add Page previews pattern to M101) covered in https://github.com/wikimedia/WikimediaUI-Style-Guide/pull/380
- Tipsy (see T117720: Remove use of jquery.tipsy from Wikimedia-maintained code and T88630: Implement a way to display tooltips (using PopupWidget) on hover/focus rather than on click)