Steps to reproduce the issue

1. Fetch the current git repo
2. run npm install

Expected result

No warnings

Actual result

npm WARN lifecycle joomla@4.0.0install: cannot run in wd joomla@4.0.0 node build.js --copy-assets && node build.js --build-check (wd=/var/www/html/joomla-cms)
npm WARN lifecycle joomla@4.0.0postinstall: cannot run in wd joomla@4.0.0 node build.js --compile-js && node build.js --compile-css && node build.js --compile-ce &&cd administrator/components/com_media && npm install && npm run build (wd=/var/www/html/joomla-cms)
npm WARN optional SKIPPING OPTIONAL DEPENDENCY: fsevents@1.2.4 (node_modules/fsevents):
npm WARN notsup SKIPPING OPTIONAL DEPENDENCY: Unsupported platform for fsevents@1.2.4: wanted {"os":"darwin","arch":"any"} (current: {"os":"linux","arch":"x64"})

audited 8149 packages in 7.427s
found 10 vulnerabilities (9 low, 1 high)
run npm audit fix to fix them, or npm audit for details

System information (as much as possible)

Current 4.0-dev Branch on Ubuntu 18.04

Additional comments

I have just rebuilt my system. Joomla is now working. But: I'm worried about the warnings. Did I do something wrong?

$ node --version
v10.13.0
$ npm --version
6.4.1