In the repository, for v10.20.0 we have https://github.com/nodejs/node/blob/v10.20.0/src/node_api.h#L702 which, at that line, has the correct guard. When unpacking https://nodejs.org/dist/v10.20.0/node-v10.20.0-headers.tar.xz and examining node_api.h the guard found there is `#ifdef NAPI_EXPERIMENTAL` which is wrong, rather than `#if NAPI_VERSION >= 6`