Heroku - '#heroku/buildpack-registry not accessible from #heroku-cli/plugin-buildpacks' - node.js

Question

I am attempting to launch my Nuxt SSR/Universal app through Heroku, due to Netlify no longer meeting my needs (I need backend functionality). By following the tutorial here, and then trying to deal with subsequent errors through use of third-party buildpacks, and I ended up at the following error:
npm ERR! #heroku/buildpack-registry not accessible from #heroku-cli/plugin-buildpacks
full output for context:
-----> Node.js app detected
-----> Creating runtime environment
NPM_CONFIG_LOGLEVEL=error
NPM_CONFIG_PRODUCTION=false
NODE_ENV=production
NODE_MODULES_CACHE=true
NODE_VERBOSE=false
-----> Installing binaries
engines.node (package.json): 14.x
engines.npm (package.json): unspecified (use default)
Resolving node version 14.x...
Downloading and installing node 14.15.0...
Using default npm version: 6.14.8
-----> Installing dependencies
Installing node modules
npm ERR! #heroku/buildpack-registry not accessible from #heroku-cli/plugin-buildpacks
npm ERR! A complete log of this run can be found in:
npm ERR! /tmp/npmcache.dVBXd/_logs/2020-11-01T03_35_25_039Z-debug.log
-----> Build failed
We're sorry this build is failing! You can troubleshoot common issues here:
https://devcenter.heroku.com/articles/troubleshooting-node-deploys
If you're stuck, please submit a ticket so we can help:
https://help.heroku.com/
Love,
Heroku
! Push rejected, failed to compile Node.js app.
! Push failed
As near as I can tell, there isn't a buildpack-registry folder on my local copy of #heroku, so I don't know what that folder is supposed to have. I have the Heroku CLI for npm, and running heroku buildpacks gets me:
1. heroku/nodejs
2. https://github.com/stomita/heroku-buildback-phantomjs.git
which should all be valid. I've tried deploying on a clean environment with the same result.
Sorry if the question is a bit rambly, I just have no idea where to start trying to figure this out.

Answer 1

It urns out I forgot to install some packages the #heroku-cli requires. Running the following install command fixed it for me, but you may be missing packages that I have, or I may be missing packages that you have.
npm i #heroku/buildpack-registry async-file cli-ux got phoenix
I was initially confused because there was no #heroku module, but it was only accessible as the #heroku/buildpack-registry