diff --git a/doc_src/index.hdr.in b/doc_src/index.hdr.in
index 80e8bed7c..707944d2f 100644
--- a/doc_src/index.hdr.in
+++ b/doc_src/index.hdr.in
@@ -834,7 +834,9 @@ The user can change the settings of `fish` by changing the values of certain var
 
 - `fish_history`, the current history session name. If set, all subsequent commands within an
   interactive fish session will be logged to a separate file identified by the value of the
-  variable. If unset, or set to `default`, the default session name "fish" is used.
+  variable. If unset, or set to `default`, the default session name "fish" is used. If set to an
+  empty string, history is not saved to disk (but is still available within the interactive
+  session).
 
 - `fish_user_paths`, an array of directories that are prepended to `PATH`. This can be a universal variable.