diff --git a/man/certspotter-script.md b/man/certspotter-script.md
index 978d645..9264a8c 100644
--- a/man/certspotter-script.md
+++ b/man/certspotter-script.md
@@ -78,7 +78,8 @@ The following environment variables are set for `discovered_cert` events:
 
 `TEXT_FILENAME`
 
-:    Path to a file containing a text representation of the certificate.
+:    Path to a file containing a text representation of the certificate.  This file contains the same text that
+     certspotter uses in emails.  You should not attempt to parse this file because its format may change in the future.
      Not set if `-no_save` was used.
 
 `NOT_BEFORE`, `NOT_BEFORE_UNIXTIME`, `NOT_BEFORE_RFC3339`