diff --git a/.gitattributes b/.gitattributes
index fe07ee6a..8e8a2e8a 100644
--- a/.gitattributes
+++ b/.gitattributes
@@ -2,6 +2,9 @@
 .gitignore export-ignore
 * text=auto eol=lf
 
+# vendored files
+src/decNumber/** linguist-vendored
+
 # generated files
 src/lexer.[ch] linguist-generated=true
 src/parser.[ch] linguist-generated=true