diff --git a/content/build/building/variables.md b/content/build/building/variables.md
index e66bb9c244..a558b1d990 100644
--- a/content/build/building/variables.md
+++ b/content/build/building/variables.md
@@ -366,6 +366,7 @@ Sets the type of the BuildKit progress output. Valid values are:
 - `auto` (default)
 - `plain`
 - `tty`
+- `rawjson`
 
 Usage: