ISO/IEC TR 24028:2020 9.3.1: Explainability: general
Explainability, the ability to give humans understandable reasons for an AI system's outputs or behaviour, mitigates opaqueness and supports accountability and appropriate reliance.
This control maps to 8 controls across 3 other frameworks. If you already hold one of them, the evidence you collected for it is the starting point here rather than new work.