The domain cydia.invoxiplaygames.uk is a well-known repository in the legacy jailbreak community
Further Reading & Resources
Installation: Typically, you visit the certificate page on your legacy device's Safari browser to install the ISRG Root X1 certificate directly. cydia.invoxiplaygames.uk certificates
If the risks outweigh the benefits, consider these safer alternatives for installing third-party iOS apps: The domain cydia