I was building a simple React app using Tailwind. I used create-react-app and then installed tailwind. I have done this many times before.

In order to install Tailwind, I also had to install craco and change package.json "scripts" to use craco, like so:

"scripts": {
    "start": "craco start",
    "build": "craco build",
    "test": "craco test",
    "eject": "react-scripts eject"
  }

However, this time, when I ran npm start, I got an error that I had never encountered before:

Error: error:0308010C:digital envelope routines::unsupported

So I searched on StackOverflow and someone suggested adding --openssl-legacy-provider to my "start" script like this:

"scripts": {
    "start": "craco --openssl-legacy-provider start",
    "build": "craco build",
    "test": "craco test",
    "eject": "react-scripts eject"
  }

And it's working now. But can somebody please explain to me what --openssl-legacy-provider actually is and how it works?