How to reproduce:
1. Open user-submitted project (InoutInCginc.zip)
2. Inspect the shader files located in Assets/Lib folder(testDepthBufferFetch and testDepthBufferFetch1)
3. Select each Shader, click the arrow next to 'Compile and show code' and select 'GLES3x'
4. Click 'Compile and show code'
5. Compare both compiled files

Expected result: Compiled-Unlit-testDepthBufferFetch.shader contains "#extension GL_EXT_shader_framebuffer_fetch : enable"
Actual result: Compiled-Unlit-testDepthBufferFetch.shader does not contain "#extension GL_EXT_shader_framebuffer_fetch : enable"

Reproducible with: 2018.4.26f1, 2019.4.8f1, 2020.1.3f1, 2020.2.0a20

Notes:
The only difference between testDepthBufferFetch and testDepthBufferFetch1 is that a portion of the code for testDepthBufferFetch is in a cginc file