Many "free" services are hosted by malicious actors to inject ads or viruses into your browsing session.
In the context of 3D design (often used with V-Ray or Enscape), a "proxy" is a placeholder for high-poly objects (like detailed trees or furniture) to prevent software lag. reflect4 proxy list upd free portable
(Proceed with one of the options if you'd like.) Many "free" services are hosted by malicious actors