Nextcloud安全检查时报错
The “Referrer-Policy” HTTP header is not set to “no-referrer”, “no-referrer-when-downgrade”, “strict-origin” or “strict-origin-when-cross-origin”. This can leak referer information.
这个是NextCloud新版本提升了安全要求，解决方法就是添加对应的标记
server {
# Configuration
add_header Referrer-Policy no-referrer always;
}
完成之后重启nginx，问题解决。
这个官方论坛上有说明，多去看看
https://help.nextcloud.com/t/the-referrer-policy-http-header-is-not-set-to-no-referrer/36613