A private NPM registry might faciliate Experimental Plugin Deployment. This began life in a conversation on github about wiki plugin development and npm scopes. link 
package.json can specify a private repo:
"private" : true, "publishConfig" : { "registry" : "http://my-internal-registry.local" }
It also looks pretty easy to configure the npm CLI to prefer a local registry:
npm config set registry="http://my-internal-registry.local"
Verdaccio README shows CLI examples providing the registry per-command: github
npm adduser --registry http://localhost:4873 npm publish --registry http://localhost:4873
Pretty sure this works too:
npm install --registry http://localhost:4873 wiki
See also:
• unpm (micro npm) npm