/etc/nginx/scgi_params is in nginx-common 1.4.6-1ubuntu3.
This file is owned by root:root, with mode 0o644.
The actual contents of the file can be viewed below.
1 2 3 4 5 6 7 8 9 10 11 12 13 14  | scgi_param	REQUEST_METHOD		$request_method;
scgi_param	REQUEST_URI		$request_uri;
scgi_param	QUERY_STRING		$query_string;
scgi_param	CONTENT_TYPE		$content_type;
scgi_param	DOCUMENT_URI		$document_uri;
scgi_param	DOCUMENT_ROOT		$document_root;
scgi_param	SCGI			1;
scgi_param	SERVER_PROTOCOL		$server_protocol;
scgi_param	REMOTE_ADDR		$remote_addr;
scgi_param	REMOTE_PORT		$remote_port;
scgi_param	SERVER_PORT		$server_port;
scgi_param	SERVER_NAME		$server_name;
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