When a person logs in, how to display his name watermark in the front of the page.
Like this:
Hi @Bayes
You would have to implement that yourself in your own build.
Since Metabase generates the visualizations based on requests, then it's possible for the person to just get the results from there and generate their own visualization, which would not have any watermarks.
EDIT: There's now an issue open about it:
https://github.com/metabase/metabase/issues/15803 - upvote by adding to the first post