@ruffpl What does the IPMI server use Java for? Does it even work? AFAIK Java plugins are no longer supported by modern browsers since most dropped NPAPI support several years ago.
My guess is some outdated Javascript (not to be confused with Java itself!) on your site is trying to check for a Java plugin installation and fails so shows that popup.
There are several different ways to approach this problem to get rid of the warning:
You control the server, so you might be able to just delete the script from running by editing the source code, deleting it outright, or maybe some options.
You could disable Javascript for the site, but this will likely break other functionality.
You could find the script that triggers this warning and block it using either Vivaldi's built-in blocker (only in Snapshot for now), or an extension like uBlock Origin/uMatrix. You can find this with some detective work, either examining the source of the site or looking in the network tab of Devtools (F12).
Gets a bit technical, but I assume anyone running IPMI on their own server knows their way around web protocols
