diff --git a/lib/linguist/languages.yml b/lib/linguist/languages.yml
index 9faff3af..14519a61 100644
--- a/lib/linguist/languages.yml
+++ b/lib/linguist/languages.yml
@@ -3813,6 +3813,7 @@ XML:
   - .xliff
   - .xmi
   - .xml.dist
+  - .xproj
   - .xsd
   - .xul
   - .zcml