RGB Compressed ETC2 texture format

I have a question related to the RGB Compressed ETC2 and RGBA Compressed ASTC formats.
In the manual it states that on Android it is partially supported:

RGB Compressed ETC2 - Except on OpenGL ES 2.0; there ETC2 textures are decompressed into the ETC2 fallback format specified in the Android Build Settings or on the Android tab for the Platform-specific overrides.

RGBA Compressed ASTC - Requires Vulkan or GL_KHR_texture_compression_astc_ldr OpenGL ES extension.

In case some device doesn't support Vulkan or GL_KHR_texture_compression_astc_ldr what happens? Will the application close? Will the image exhibit artifact? Will it be converted to some other supported standard format?

The same question follows for RGB Compressed ETC2

 

Why not test?

Forum posts: https://forum.unity.com/threads/warning-rgba-compressed.1208101/

Imply that when extensions are not available, the game will used uncompressed textures, and may run out of RAM in the process.

 

Thanks for the answer.
I'm going to test it, but my fear is that my game will start raining errors and be limited by google due to the bad behavior of the app.
But the game is already set for only devices above 1gb of ram and GLES3 and newer.
I hope it works