what is admin jwt secret in strapi v3

Question

When ever I create a strapi environment with npx create-strapi-app The server.js file in config folder has this admin jwt secret environment variable what is it used for

module.exports = ({ env }) => ({
  host: env('HOST', '0.0.0.0'),
  port: env.int('PORT', 1337),
  admin: {
    auth: {
      secret: env('ADMIN_JWT_SECRET', 'dfee1c43fb8d2e506ad627'),
    },
  },
});