diff --git a/src/syntax_mapping/builtins/unix-family/50-diff.toml b/src/syntax_mapping/builtins/unix-family/50-diff.toml
new file mode 100644
index 00000000..2998d9c5
--- /dev/null
+++ b/src/syntax_mapping/builtins/unix-family/50-diff.toml
@@ -0,0 +1,3 @@
+# .debdiff is the extension used for diffs in Debian packaging
+[mappings]
+"Diff" = ["*.debdiff"]