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

{
  "name": "devil-glitches",
  "version": "0.0.1",
  "description": "glitches are invading our world, help the guardian to keep it free",
  "main": "index.js",
  "scripts": {
    "clean": "rm -rf build/; mkdir -p build target",
    "compileglsl": "./scripts/compileglsfiles.sh src/shaders build",
    "concat": "./scripts/concat.sh > build/build.js",
    "uglify": "uglifyjs build/build.js -c --screw-ie8 -m -o build/build.min.js",
    "minify": "ccjs build/build.js --compilation_level=ADVANCED_OPTIMIZATIONS > build/build.min.js",
    "nominify": "cp build/build.js build/build.min.js",
    "gen": "cp src/index.html target/index.html && cp build/build.min.js target/b.js",
    "build-nominify": "npm run clean && npm run compileglsl && npm run concat && npm run nominify && npm run gen",
    "zip": "cd target; zip -r ../target.zip .; cd ..; wc -c target.zip",
    "build": "export NODE_ENV=production; npm run clean && npm run compileglsl && npm run concat && npm run minify && npm run gen && npm run zip",
    "watch": "npm run build-nominify; wr 'npm run build-nominify' src/ scripts/",
    "liveserver": "mkdir -p target; cd target; live-server --no-browser",
    "start": "npm run watch & npm run liveserver"
  },
  "repository": {
    "type": "git",
    "url": "git+https://github.com/agar3s/devil-glitches.git"
  },
  "keywords": [
    "js13k"
  ],
  "author": "Agar3s",
  "license": "ISC",
  "bugs": {
    "url": "https://github.com/agar3s/devil-glitches/issues"
  },
  "homepage": "https://github.com/agar3s/devil-glitches#readme",
  "devDependencies": {
    "glslmin": "0.0.0",
    "nodemon": "^1.10.0",
    "uglifyjs": "^2.4.10",
    "wr": "^1.3.1"
  },
  "dependencies": {
    "closurecompiler": "^1.6.0"
  }
}


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.