result.sources from the Bing AI Mode endpoint lists the pages that Bing read for the answer, in the order of the Reading sources and understanding step of the reasoning panel. The “+N more” pages are included. Any other page that a citation pill links comes after them. The source cards below the answer are pages from this list.
Each source has the common sources structure: position, url, label and, when Bing shows a snippet, description.

Reasoning panel and source cards in Bing AI Mode
Example
Request
Response