Reproduction steps:
1. Create a new 3D URP project
2. Click Windows > Package Manager
3. In the Package Manager window, add the “com.unity.toonshader” package
4. Observe the Console window

Expected results: No errors are thrown
Actual results: Errors are thrown, indicating, that the package could not open files “UCTS_ShadowCaster_tess.cginc“ and “UCTS_Outline_tess.cginc“.

Reproduced with: 0.10.1-preview (2021.3.41f1, 2022.3.39f1, 6000.0.12f1)

Reproduced on: Ubuntu 22.04
Not reproduced on: Windows

Notes:
- in “/Library/PackageCache/com.unity.toonshader/Runtime/Legacy/Shaders“ there are files “UCTS_Outline_Tess.cginc” and “UCTS_ShadowCaster_Tess.cginc“ indicating, that the package assumes the file system is not case-sensitive which Linux isn’t.