What is the USB port power output?

Apples spec page for the MacBook Air (M1, 2020) Systems specs Which does not list the USB-C USB4 output power!

Sadly the standards are not cut and dry as it depends on what the two devices agree to per the Release 2.0 - USB Type-C Cable and August 2019 Connector Specification:

Three current level advertisements at 5V VBUS are defined by USB Type-C Current:

• Default is the as-configured for high-power operation current value as defined by a USB Specification (500 mA for USB 2.0 ports; 900 mA or 1,500 mA for USB 3.2 ports operating in single-lane or dual-lane, respectively)

• USB Type-C Current @ 1.5 A

• USB Type-C Current @ 3.0 A

There is a clear functional distinction between advertising Default versus the USB Type-C Current at either 1.5 A or 3.0 A.

• Default is intended for host operation in providing bus power to a connected device where the host manages the device’s current consumption for the low-power, high- power and suspend states as defined in the USB base specifications.

• USB Type-C Current at either 1.5 A or 3.0 A is primarily intended for charging applications. The Sink can vary its current draw up to the advertised limit. Offering USB Type-C Current at either 1.5 A or 3.0 A is allowed for a host providing bus power to a device. The host needs to assume that the device will continuously draw up to the offered limit.

Here’s a bit more on USB-C & USB4

• USB 3, USB 4, Thunderbolt, & USB-C — everything you need to know
• USB4: What’s Different and Why It Matters
• USB 4 specs and features: Everything you need to know about the new double-speed USB