Hi.
What is full bleed background (Safari 15+) and how is it used?
Is there a sample picture where the effect is shown?
Mr. F.
You can view it on this slack by going to the Safari advanced preferences and turning off this checkbox:
The color there is controlled by that setting, and it defaults to the background color. We should change how that’s shown in the UI, “full bleed” is not clear.
Got it. But i think it has to set “on” 
And in the preferences - tab: compact tab view must be chosen.
Then the tab shows the selected color.
Mr. F.