Injected variable wrapped with double quotes

[Rc85]

Current behaviour 💣

Inject a string variable to my HTML file has double quotes around it.

Expected behaviour ☀️

Should not have double quotes.

Reproduction Example 👾

Environment 🖥

https://codesandbox.io/s/wild-night-mqm26?file=/webpack.config.js

1. Create a new terminal
2. Execute yarn start to run webpack serve
3. Press refresh in the sandbox browser
4. See "This is foo" wrapped in double quotes

The codesandbox uses webpack 5. The one I'm using in my development is webpack 4. Both have double quotes.

[Rc85]

JSON.stringify adds the double quote.