It is not required to have that asset for the export to work, and the shader size bloat might be insignificant. If the build size and runtime performance are acceptable, please feel free to ignore this message.
No Assets/Luna.shadervariants asset was found. This might bloat your build with excessive shader variants.
Luna exports only the shader variants that appear to be in use from Unity Editor's point of view. This, however, means that the total number of variants exported is probably excessive and can be reduced, bringing down the build size, decreasing startup time and (slightly) improving build time.
It is recommended to consider baking shader variants used by the build as outlined in Shaders optimization tutorial.
Low / Medium
Please refer to this tutorial for troubleshooting steps.