Why does exports: true add an export for the package.json file?

[uncenter]

When I enable the auto exports feature, my exports look like this:

	"exports": {
		".": {
			"import": "./dist/index.mjs",
			"require": "./dist/index.cjs"
		},
+		"./package.json": "./package.json"
	},

Why does tsdown add the "./package.json" field to exports and what purpose does this serve? It seems to be the expected behavior given its appearance in the test cases of the initial implementation (4707c37).

[uncenter]

I think I have figured it out. https://nodejs.org/api/packages.html#package-entry-points:

Existing packages introducing the "exports" field will prevent consumers of the package from using any entry points that are not defined, including the package.json (e.g. require('your-package/package.json')). This will likely be a breaking change.

I assume that it is because of backwards compatibility that this field is added? I think it would be helpful if this was documented on https://tsdown.dev/options/package-exports as for legacy reasons?

[sxzz]

Yes, exactly. Compatibility is one reason. Also, I think package.json contains basic package information, so it is reasonable to export it by default.

This is controlled by exports.packageJson, which defaults to true:
https://tsdown.dev/reference/api/Interface.ExportsOptions#packagejson

If you don’t need it, you can disable this option.