Google has a new (I think new) filter in the Google Search Console Performance report named Cross-language Results. I have never seen this filter, but I suspect this is related to if Google Search will take other languages, translate them for you, and include them in the search results.
This was spotted by Praveen Sharma and posted on Twitter - here is his screenshot:
Google has an old help document that is not live on the current site, but is available in the Wayback machine that explains cross-language search results as, pages are selected based on our analysis of where the biggest information gaps exist in various languages, and the quality and relevance of a candidate page to the user's query. This means that if lots of high quality pages are already available in a certain language, then there is less need for cross-language search results to fill the gap. Cross-language search activates only when Google can't find a high-quality answer in the user's query language.
So I assume this is Google's way to show you when Google does this in Search and if it impacts your pages or not.
Have you seen this filter before in Search Console?
Forum discussion at Twitter.