diff --git a/.gitattributes b/.gitattributes
index e19106b7fe..1be02425ca 100644
--- a/.gitattributes
+++ b/.gitattributes
@@ -5,9 +5,13 @@
 # Asset files are not Unity, but Lua instead
 *.asset linguist-language=Lua
 # We have some SPICE frame kernels that get misclassified as code
-.tf -linguist-detectable
+*.tf -linguist-detectable
 # We don't want to index the GDAL csv and xml files
 modules/globebrowsing/gdal_data/* linguist-vendored
+# No need to index any external files
+*/ext/* linguist-vendored
+# No C allowed
+*.h linguist-language=C++
 
 # GitHub files
 ATTRIBUTION text