The upstream project declares ISC in package.json. Original declaration follows:

{
  "name": "space-js13k2021",
  "version": "1.0.0",
  "description": "",
  "main": "index.js",
  "scripts": {
    "dev": "onchange -i 'src/**/*.js' -- npm run build",
    "dev:mid": "onchange -i 'src/**/*.js' -- npm run build:mid",
    "dev:fast": "onchange -i 'src/**/*.js' -- npm run build:fast",
    "build": "npm run compile && npm run package",
    "build:mid": "npm run compile && npm run package:mid",
    "build:fast": "npm run compile && cat dist/bundle.js > dist/bundle.min.js && npm run html",
    "compile": "rollup src/main.js --format es --no-strict --file dist/bundle.js",
    "package": "npm run minify && npm run roadroller && npm run html && npm run zip && npm run status",
    "package:mid": "npm run minify && npm run html && npm run zip && npm run status",
    "minify": "uglifyjs --compress --mangle -o dist/bundle.min.js -- dist/bundle.js",
    "roadroller": "roadroller dist/bundle.min.js -o dist/bundle.min.js --optimize 2",
    "html": "node src/build-html.js",
    "zip": "zip dist/build.zip index.html",
    "status": "echo \"===> Build Size: $(wc -c < dist/build.zip) / 13,312 bytes <===\""
  },
  "repository": {
    "type": "git",
    "url": "git+https://github.com/arikwex/space-js13k2021.git"
  },
  "author": "",
  "license": "ISC",
  "bugs": {
    "url": "https://github.com/arikwex/space-js13k2021/issues"
  },
  "homepage": "https://github.com/arikwex/space-js13k2021#readme",
  "devDependencies": {
    "nodemon": "^2.0.12",
    "onchange": "^7.1.0",
    "roadroller": "git+https://github.com/lifthrasiir/roadroller.git",
    "rollup": "^2.56.3",
    "uglify-js": "^3.14.1"
  }
}


ISC license terms:

Permission to use, copy, modify, and/or distribute this software for any
purpose with or without fee is hereby granted, provided that the above
copyright notice and this permission notice appear in all copies.

THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.