diff --git a/.gitmodules b/.gitmodules
new file mode 100644
index 00000000..2524803c
--- /dev/null
+++ b/.gitmodules
@@ -0,0 +1,3 @@
+[submodule "tool/cf_email_decoder"]
+	path = tool/cf_email_decoder
+	url = https://codeberg.org/smege1001/cf_email_decoder.git
diff --git a/tool/cf_email_decoder b/tool/cf_email_decoder
new file mode 160000
index 00000000..a7fabb18
--- /dev/null
+++ b/tool/cf_email_decoder
@@ -0,0 +1 @@
+Subproject commit a7fabb1837b55f6b7514d0f7a1587671539033a6