That's the feature that allows a user to enter a query (a name, keyword, or phrase) and search across all available content categories (e.g., profiles, posts, media, documents, messages) instead of limiting to one specific category like "Users," "Videos," or "Discussions."
(or Universal Search )
It looks like you're referencing a search interface (possibly from a database, forum, or content platform). The proper for "Searching for: Lena Polanski in: All Categories" would be:
