I understand you're looking for the file. However, I need to provide some important clarifications and guidance.
Torrent sites (unless checksum-verified), “MacDownload.org” clones, and any site asking for credit card info. Genuine Catalina is free . Mac Os Catalina 10.15 7 Dmg Download
You cannot download the Catalina installer directly from Apple on Windows or Linux. However, third-party sources host verified copies. I understand you're looking for the file
Be extremely cautious with third-party DMG downloads from sites like: Mac Os Catalina 10.15 7 Dmg Download