diff --git a/runtime/lua/vim/filetype.lua b/runtime/lua/vim/filetype.lua
index df26df9e15..88609799bf 100644
--- a/runtime/lua/vim/filetype.lua
+++ b/runtime/lua/vim/filetype.lua
@@ -972,11 +972,13 @@ local extension = {
   Sysx = 'rapid',
   SysX = 'rapid',
   SYSX = 'rapid',
+  SYSx = 'rapid',
   modx = 'rapid',
   modX = 'rapid',
   Modx = 'rapid',
   ModX = 'rapid',
   MODX = 'rapid',
+  MODx = 'rapid',
   rasi = 'rasi',
   rbs = 'rbs',
   rego = 'rego',