diff --git a/README.md b/README.md
index 1cee0c5..f29102f 100644
--- a/README.md
+++ b/README.md
@@ -17,6 +17,8 @@ Although this is not a malicious error, and typical users aren't Tweeting weird
 
 Feel free to send a pull request to add more strings, or additional sections. However, please do not send pull requests with very-long strings (255+ characters), as that makes the list much more difficult to view.
 
+Likewise, please do not send pull requests which compromise *manual usability of the file*. This includes the [EICAR test string](https://en.wikipedia.org/wiki/EICAR_test_file), which can cause the file to be flagged by antivirus scanners, and files which alter the encoding of `blns.txt`.
+
 ## Disclaimer
 
 The Big List of Naughty Strings is intended to be used *for software you own and manage*. Some of the Naughty Strings can indicate security vulnerabilies, and as a result using such strings with third-party software may be a crime. The maintainer is not responsible for any negative actions that result from the use of the list.
diff --git a/blns.json b/blns.json
index 51ac199..4c4d078 100644
--- a/blns.json
+++ b/blns.json
@@ -1,6 +1,7 @@
 [
   "", 
   "undefined", 
+  "undef",
   "null", 
   "NULL", 
   "nil", 
diff --git a/blns.txt b/blns.txt
index f9672fd..6060f9c 100644
Binary files a/blns.txt and b/blns.txt differ
diff --git a/scripts/txt_to_json.py b/scripts/txt_to_json.py
index 0575e88..5569efb 100644
--- a/scripts/txt_to_json.py
+++ b/scripts/txt_to_json.py
@@ -6,7 +6,7 @@ import json
 
 with open('../blns.txt', 'r') as f:
 
-	# put all lines in the file into a Python list
+    # put all lines in the file into a Python list
     content = f.readlines()
     
     # above line leaves trailing newline characters; strip them out
@@ -22,4 +22,4 @@ with open('../blns.json', 'wb') as f:
 
 	# write JSON to file; note the ensure_ascii parameter
 	json.dump(content, f, indent=2, ensure_ascii=False)
-    
\ No newline at end of file
+