third_party/skia/resources/sksl/shared/Caps.sksl

void main() {
    int x = 0;
    int y = 0;
    int z = 0;
    if (sk_Caps.externalTextureSupport) x = 1;
    if (sk_Caps.fbFetchSupport) y = 1;
    if (sk_Caps.canUseAnyFunctionInShader) z = 1;
    sk_FragColor.rgb = half3(x, y, z);
}