Private mode for tab
I have suggest add to vivaldi in normal window the private mode for tab.
Yes, would be nice-to-have.
If you think a feature is useful and missing in Vivaldi, please make a request.
How to make a feature request for Vivaldi
If you think your problem can be solved by a missing feature, please add a request at https://forum.vivaldi.net/category/48/features-requests in the corresponding thread for your browser version.
Add one line in bold as a short title for the feature and 2-3 lines to describe the wanted feature.