diff --git a/reference/filesystem/functions/fread.xml b/reference/filesystem/functions/fread.xml
index 20bd6d4501..4ff50e73be 100644
--- a/reference/filesystem/functions/fread.xml
+++ b/reference/filesystem/functions/fread.xml
@@ -37,7 +37,10 @@
     </listitem>
     <listitem>
      <simpara>
-      8192 bytes have been read (after opening userspace stream)
+      if the stream is read buffered and it does not represent a plain file, at
+      most one read of up to a number of bytes equal to the chunk size (usually
+      8192) is made; depending on the previously buffered data, the size of the
+      returned data may be larger than the chunk size.
      </simpara>
     </listitem>
    </itemizedlist>