Add existing to tracked

node_modules/@cesium/engine/Source/Shaders/BufferPolygonMaterialFS.js

@@ -0,0 +1,15 @@
+//This file is automatically rebuilt by the Cesium build process.
+export default "in vec4 v_pickColor;\n\
+in vec4 v_color;\n\
+\n\
+void main()\n\
+{\n\
+    if (v_color.a < 0.005)   // matches 0/255 and 1/255\n\
+    {\n\
+        discard;\n\
+    }\n\
+\n\
+    out_FragColor = czm_gammaCorrect(v_color);\n\
+    czm_writeLogDepth();\n\
+}\n\
+";