This summary is not the rule. The rule text controls.
If your case involves a law from another country, and you plan to bring that up, you have to tell the other side ahead of time. You do this in writing, either in a pleading or some other formal document. You can't spring it on them during trial without warning.
When the judge needs to figure out what that foreign law actually says, they aren't limited to what the parties hand them. The judge can look at any source that seems helpful, including expert testimony, even if nobody officially submitted it as evidence or if it wouldn't normally be allowed in court. This gives judges more freedom to research and understand foreign law than they'd have with typical Nevada or U.S. legal questions.
Finally, once the judge decides what the foreign law means, that decision counts as a ruling on a legal question, not a factual one. This matters because it affects things like how the decision can be appealed later on.
