I've noticed that QWebEngine set word-wrap by default to tooltips (set by title attribute). Here's some screenshots using QWebEngine and other browsers (Chrome, Firefox, Opera and Edge):
Other browsers :
QWebEngine :
And here's the link for the sample above, so you can reproduce the bug, and check if it's truly a bug.
- relates to
- 
                    QTBUG-41051 Adjustable tooltip widths (also for non-rich-text tooltips) -         
- Open
 
-         
- resulted in
- 
                    QTBUG-76122 Hover-over text does not wrap -         
- Closed
 
-         
| For Gerrit Dashboard: QTBUG-72021 | ||||||
|---|---|---|---|---|---|---|
| # | Subject | Branch | Project | Status | CR | V | 
| 249380,4 | Do not force wrapping of tooltips | 5.12 | qt/qtwebengine | Status: MERGED | +2 | 0 |