Improve wording for the load hook

docs/05-plugin-development.md

@@ -104,7 +104,7 @@ If `false` is returned for `moduleSideEffects` and no other module imports anyth
 
 See [synthetic named exports](guide/en/#synthetic-named-exports) for the effect of the `syntheticNamedExports` option. If `null` is returned or the flag is omitted, then `syntheticNamedExports` will be determined by the first `resolveId` hook that resolved this module or eventually default to `false`. The `transform` hook can override this.
 
-See [custom module meta-data](guide/en/#custom-module-meta-data) for how to use the `meta` option. If `null` is returned or the option is omitted, then `meta` will be determined by the first `resolveId` hook that resolved this module or eventually default to an empty object. The `transform` hook can add or replace properties of this object.
+See [custom module meta-data](guide/en/#custom-module-meta-data) for how to use the `meta` option. If a `meta` object is returned by this hook, it will be merged shallowly with any `meta` object returned by the resolveId hook. If no hook returns a `meta` object it will default to an empty object. The `transform` hook can further add or replace properties of this object.
 
 You can use [`this.getModuleInfo`](guide/en/#thisgetmoduleinfomoduleid-string--moduleinfo) to find out the previous values of `moduleSideEffects`, `syntheticNamedExports` and `meta` inside this hook.