diff --git a/doc/extensions_notes.md b/doc/extensions_notes.md
index 41365849b..f42823d64 100644
--- a/doc/extensions_notes.md
+++ b/doc/extensions_notes.md
@@ -13,7 +13,8 @@ The Proxmark3 client uses a wide range of files. Here is a brief recap to get yo
 | .elf | binary proxmark3 device firmware file. |
 | .cmd | text file, contains proxmark3 client commands used to call client with -s |
 | .lua | text file, contains lua script to be run inside client.  or called with -l |
-| .pm3 | text file, with numbers ranging 0-255 or -127 - 128.  Contains trace signal data for low frequency tags (data load) |
+| .pm3 | text file, with numbers ranging 0-255 or -127 - 128.  Contains trace signal data for low frequency tags (data load / data save) |
+| .wav | binary file,  PCM8 with samplerate 125000,  one channel. (data save)
 | .trace | binary file,  contains trace log data usually from high frequency tags.  (hw trace load) |
 | .log | text file, our log file, contains the output from almost all commands you run inside Proxmark3 client |
-| .history | text file, our command log file, contains the commands you ran inside Proxmark3 client |
+| .history | text file, our command log file, contains the commands you ran inside Proxmark3 client |
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