+.. nmconfig:: index.as_text
+
+ List of regular expressions (without delimiters) for MIME types to
+ be indexed as text. Currently this applies only to attachments. By
+ default the regex matches anywhere in the content type; if the
+ user wants an anchored match, they should include anchors in their
+ regexes.
+
+ History: This configuration value was introduced in notmuch 0.38.
+