diff --git a/.gitmodules b/.gitmodules
index 433e824..6c590c2 100644
--- a/.gitmodules
+++ b/.gitmodules
@@ -43,3 +43,6 @@
 [submodule "simple-comment-markup"]
 	path = lisp/simple-comment-markup
 	url = https://git.tecosaur.net/tec/simple-comment-markup.git
+[submodule "conf-data-toml"]
+	path = lisp/conf-data-toml
+	url = https://github.com/tecosaur/conf-data-toml.git
diff --git a/config.org b/config.org
index d262356..0ce0ca0 100644
--- a/config.org
+++ b/config.org
@@ -13370,6 +13370,24 @@ Julia is also missing a mime type, but that's not too hard to fix.
 update-mime-database ~/.local/share/mime
 #+end_src
 
+** Data.toml files
+
+#+call: confpkg("conf-data-toml")
+
+For =DataToolkit.jl=-formatted TOML files, I've made a major mode.
+
+#+begin_src emacs-lisp :tangle packages.el
+(package! conf-data-toml :recipe (:local-repo "lisp/conf-data-toml"))
+#+end_src
+
+Since the major mode is autoloaded, all we need to do is register an appropriate
+magic command for it to be used in =Data.toml= files.
+
+#+begin_src emacs-lisp
+(use-package! conf-data-toml
+  :magic ("\\`data_config_version = [0-9]" . conf-data-toml-mode))
+#+end_src
+
 ** Graphviz
 
 #+call: confpkg("!Pkg graphviz-dot-mode")
diff --git a/lisp/conf-data-toml b/lisp/conf-data-toml
new file mode 160000
index 0000000..b40d8b0
--- /dev/null
+++ b/lisp/conf-data-toml
@@ -0,0 +1 @@
+Subproject commit b40d8b078a616e79a6e8e4a88d8af2c86257f3a5