Glossary
System.Search.AutoSummary
Windows Search property holding an automatic summary of a document's text content: in practice an extract that can survive after the file is deleted.
Microsoft describes System.Search.AutoSummary as an automated summary of the full text contents of a document. In the index it is an extract of the beginning of the text; Stroz Friedberg's 2023 research reports up to the first 1,024 bytes on Windows 11.
It exists only for content-indexed file types in indexed locations. Because the index lags behind the disk, it can hold the text of files deleted since, such as notes, scripts or saved credentials. It reflects the content at indexing time. See evidence of deleted files in the Windows Search index.