Informal.

This is coolbert:

India. USA. Australia. Japan. The Quad.

An informal alliance between nations in the Indo-Pacific region the importance of which of recent has become much more significant 

From The Diplomat and the article by Sumitha Narayanan Kutty and Rajesh Basrur.

1. "The Quad: What It Is – And What It Is Not"

"The Quad is no Asian NATO. And that may be its greatest strength."

"The March 12 [2021] summit meeting of the Quadrilateral Security Dialogue or Quad, comprising the United States, India, Japan, and Australia, has not been fully grasped by most analysts. The Quad’s recent resurgence – after an abortive start in 2007 – has been driven by uneasiness about the rise of China and the security threat it poses to the international order."

2. "Biden to Host First In-Person Quad Summit With Eye on China"

"Strengthening ties between the US, Japan, Australia, and India is a key aspect of Biden's strategy against China"

Thanks to the Internet web site Anti-War and the article by Dave DeCamp

"President Biden will host the leaders of Japan, India, and Australia at the White House on September 24th [2021]. The summit will mark the first in-person meeting between the leaders of the Quad, a four-nation group that the Biden administration seeks to strengthen as part of its anti-China strategy."

Indeed. All eyes on China now it seems. Quad represents Grand Strategy in the classical sense. As does AUKSA. Machinations and maneuver among nations, forming alliances formal and informal with geo-political considerations in mind.

coolbert.