There is currently a warning in the specifications for the summary element:

I think this comment is outdated, and related to the fact that the old role of this element is button, which was changed in these PRs:

• Editorial: clarify summary element role mapping #434
• Correction: conditionally revise allowed attributes and roles on summary element #435

I tested the implementation of Firefox, Safari and a Chromium browser and they all did not have any role. So that makes me think that this warning is outdated.