curl_easy_duphandle.3: clarify how HSTS and alt-svc are duped

Closes #12315

diff --git a/docs/libcurl/curl_easy_duphandle.3 b/docs/libcurl/curl_easy_duphandle.3
index f66c1dffb4f0331facd0938845be9e44fcea4974..007efa57e788380946a1909bd6eb8eab81280ddf 100644 (file)
--- a/docs/libcurl/curl_easy_duphandle.3
+++ b/docs/libcurl/curl_easy_duphandle.3
@@ -45,6 +45,9 @@ The new handle does \fBnot\fP inherit any state information, no connections,
 no SSL sessions and no cookies. It also does not inherit any share object
 states or options (created as if \fICURLOPT_SHARE(3)\fP was set to NULL).
 
+If the source handle has HSTS or alt-svc enabled, the duplicate gets data read
+data from the main file name to populate the cache.
+
 In multi-threaded programs, this function must be called in a synchronous way,
 the input handle may not be in use when cloned.
 .SH EXAMPLE