The following is the May 21, 2024, Congressional Research Service report, AUKUS Pillar 2 (Advanced Capabilities): Background and Issues for Congress.
From the report
AUKUS Pillar 2 refers to a suite of cooperative activities conducted by the United States, the United Kingdom, and Australia to develop and field “advanced capabilities” under the AUKUS security partnership. To date, Pillar 2 activities have been coordinated among the three governments by a number of means, including topic-specific...
https://news.usni.org/2024/05/22/report-to-congress-on-aukus-pillar-2