Error downloading regex-tester

[Saint Michael]

git clone https://github.com/nginxinc/NGINX-Demos/tree/master/nginx-regex-tester
Cloning into 'nginx-regex-tester'...
fatal: repository
'https://github.com/nginxinc/NGINX-Demos/tree/master/nginx-regex-tester/'
not found

Any idea how can I install this software?