I might be panicking and it might be just a temporary glitch. Nonetheless, I noticed today morning npm jenkins jobs for patches in extensions/WikibaseJavaScriptApi are failing.
See e.g. failures for https://gerrit.wikimedia.org/r/#/c/387079 or https://gerrit.wikimedia.org/r/#/c/387773

I wonder whether this is somehow related to the recent switch to docker containers for npm jobs?

Possibly relevant part of npm-debug.log below:

64684 silly install phantomjs-prebuilt@2.1.15 /src/node_modules/.staging/phantomjs-prebuilt-e66e8660
64685 info lifecycle phantomjs-prebuilt@2.1.15~install: phantomjs-prebuilt@2.1.15
64686 verbose lifecycle phantomjs-prebuilt@2.1.15~install: unsafe-perm in lifecycle true
64687 verbose lifecycle phantomjs-prebuilt@2.1.15~install: PATH: /usr/local/lib/node_modules/npm/bin/node-gyp-bin:/src/node_modules/phantomjs-prebuilt/node_modules/.bin:/src/node_modules/.bin:/usr/bin:/usr/local/sbin:/usr/local/bin:/usr/sbin:/usr/bin:/sbin:/bin
64688 verbose lifecycle phantomjs-prebuilt@2.1.15~install: CWD: /src/node_modules/phantomjs-prebuilt
64689 silly lifecycle phantomjs-prebuilt@2.1.15~install: Args: [ '-c', 'node install.js' ]
64690 silly lifecycle phantomjs-prebuilt@2.1.15~install: Returned: code: 1 signal: null
64691 info lifecycle phantomjs-prebuilt@2.1.15~install: Failed to exec install script
64692 verbose unlock done using /cache/_locks/staging-1a14545af9ac12d4.lock for /src/node_modules/.staging
64693 silly rollbackFailedOptional Starting
64694 silly rollbackFailedOptional Finishing
64695 silly runTopLevelLifecycles Starting
64696 silly runTopLevelLifecycles Finishing

64700 verbose stack Error: phantomjs-prebuilt@2.1.15 install: node install.js
64700 verbose stack Exit status 1
64700 verbose stack at EventEmitter.<anonymous> (/usr/local/lib/node_modules/npm/lib/utils/lifecycle.js:239:16)
64700 verbose stack at emitTwo (events.js:106:13)
64700 verbose stack at EventEmitter.emit (events.js:191:7)
64700 verbose stack at ChildProcess.<anonymous> (/usr/local/lib/node_modules/npm/lib/utils/spawn.js:24:14)
64700 verbose stack at emitTwo (events.js:106:13)
64700 verbose stack at ChildProcess.emit (events.js:191:7)
64700 verbose stack at maybeClose (internal/child_process.js:891:16)
64700 verbose stack at Process.ChildProcess._handle.onexit (internal/child_process.js:226:5)
64701 verbose pkgid phantomjs-prebuilt@2.1.15
64702 verbose cwd /src
64703 error Linux 4.9.0-0.bpo.3-amd64
64704 error argv "/usr/bin/nodejs" "/usr/local/bin/npm" "install" "--no-progress"
64705 error node v6.11.0
64706 error npm v3.8.3
64707 error code ELIFECYCLE
64708 error phantomjs-prebuilt@2.1.15 install: node install.js
64708 error Exit status 1
64709 error Failed at the phantomjs-prebuilt@2.1.15 install script 'node install.js'.
64709 error Make sure you have the latest version of node.js and npm installed.
64709 error If you do, this is most likely a problem with the phantomjs-prebuilt package,
64709 error not with npm itself.
64709 error Tell the author that this fails on your system:
64709 error node install.js
64709 error You can get information on how to open an issue for this project with:
64709 error npm bugs phantomjs-prebuilt
64709 error Or if that isn't available, you can get their info via:
64709 error npm owner ls phantomjs-prebuilt
64709 error There is likely additional logging output above.
64710 verbose exit [ 1, true ]