I’m not sure based on my observations. Is it in bytes or in uniforms in the buffer?
On NVidia it looks like bytes, I get a return value of 65536, and I can’t define a vec4 array with 4096 entries or more.
On Intel it returns 16384 but the array with 2048 vec4’s I settled upon appears to compile without an error, but that’s 32768 bytes.