So I found this website, which is a scam since you can only download synfig from fosshub and gumroad. So beware of fake sites like this, they might inject malware.
https://synfig-studio.nl.download.it/
Do post other fake websites here so people know that they shouldn’t download synfig from them.
Thank you for the report.
In a general way, never download software from “download” sites.
Always instead from the official website or GitHub, from the original team (or from a site that is officially linked to the software from the website, like FossHub, SourceForge, GumRoad …)
Open-source is often used to propagate malwares as the source code is available and easy to alter, so it is required to take only the original versions.