Developer tool "bug"
If you never have used Vivaldi on a computer, and then use the developer tools for the first time.
Then you will see this, which points to information about another browser.
Every link points to the information about what's new in the "Chrome 59" version of developer tools and not really Chromium which it's based upon.
@zhakal May be not all information could be translated or was forgotten.
Reported issue now
VB-29344 "what's new" tab in Developer tools says: Chrome 59