Standard Cutout should be the chosen fallback shader if:
1.) The shader name contains the word "Cutout"
2.) Code contains _ALPHATEST_ON
3.) Code contains _Offset
4.) Code contains _Mode with a value of 1.0f (representing cutout enum)
However, this results in falling back to Standard Opaque.
If the shader name is edited to also include the word "Toon", then it falls back to Toon Cutout as expected.