Yarn: `archivo tar no válido` al instalar un archivo no tar

$ yarn --version
0,17,8

¿Quieres solicitar una función o informar de un error ?
característica o error de compatibilidad (con bower)

¿Cuál es el comportamiento actual?
Agregar esta dependencia a bower.json y ejecutar bower install funciona bien:

    "open-sans": "http://themes.googleusercontent.com/static/fonts/opensans/v6/cJZKeOuBrn4kERxqtaUH3T8E0i7KZn-EPnyo3HZu7kw.woff"

Intento similar con package.json falla con:

error An unexpected error occurred: "http://themes.googleusercontent.com/static/fonts/opensans/v6/cJZKeOuBrn4kERxqtaUH3T8E0i7KZn-EPnyo3HZu7kw.woff: invalid tar file".

Si el comportamiento actual es un error, proporcione los pasos para reproducirlo.
Esto debería funcionar :
yarn add http://themes.googleusercontent.com/static/fonts/opensans/v6/cJZKeOuBrn4kERxqtaUH3T8E0i7KZn-EPnyo3HZu7kw.woff

¿Cuál es el comportamiento esperado?
Espero el mismo comportamiento que bower, es decir, obtengo el archivo de fuente en un directorio local, preferiblemente con algún nombre sensible en la ruta.

Por favor, mencione su versión de node.js, yarn y sistema operativo.
archivo yarn-error.log (editado manualmente para privacidad):

Arguments: 
  /home/maxw/.nvm/versions/node/v6.9.1/bin/node /home/maxw/.nvm/versions/node/v6.9.1/bin/yarn add http://themes.googleusercontent.com/static/fonts/opensans/v6/cJZKeOuBrn4kERxqtaUH3T8E0i7KZn-EPnyo3HZu7kw.woff

PATH: 
  /home/maxw/.nvm/versions/node/v6.9.1/bin:/usr/local/sbin:/usr/local/bin:/usr/sbin:/usr/bin:/sbin:/bin:/usr/games:/usr/local/games:/snap/bin

Yarn version: 
  0.17.8

Node version: 
  6.9.1

Platform: 
  linux x64

npm manifest: 
  {
    "name": "irrelevant",
    "version": "0.0.0",
    "main": "tour.html",
    "repository": "[email protected]:irrelevant_dev/irrelevant",
    "author": "Max Waterman",
    "license": "UNLICENSED",
    "dependencies": {
      "Polymer": "^1.6.1--",
      "modernizr": "^3.3.1",
      "webcomponentsjs": "^1.0.2",
      "open-sans": "http://themes.googleusercontent.com/static/fonts/opensans/v6/cJZKeOuBrn4kERxqtaUH3T8E0i7KZn-EPnyo3HZu7kw.woff"
    },
    "resolutions": {}
  }

yarn manifest: 
  No manifest

Lockfile: 
  # THIS IS AN AUTOGENERATED FILE. DO NOT EDIT THIS FILE DIRECTLY.
  # yarn lockfile v1


  Polymer@^1.6.1--:
    version "1.6.1--"
    resolved "https://registry.yarnpkg.com/Polymer/-/Polymer-1.6.1--.tgz#6bdc3df856c7cf146c0e0153b8e4ac65137d4342"

  ansi-regex@^2.0.0:
    version "2.0.0"
    resolved "https://registry.yarnpkg.com/ansi-regex/-/ansi-regex-2.0.0.tgz#c5061b6e0ef8a81775e50f5d66151bf6bf371107"

  camelcase@^2.0.1:
    version "2.1.1"
    resolved "https://registry.yarnpkg.com/camelcase/-/camelcase-2.1.1.tgz#7c1d16d679a1bbe59ca02cacecfb011e201f5a1f"

  cliui@^3.0.3:
    version "3.2.0"
    resolved "https://registry.yarnpkg.com/cliui/-/cliui-3.2.0.tgz#120601537a916d29940f934da3b48d585a39213d"
    dependencies:
      string-width "^1.0.1"
      strip-ansi "^3.0.1"
      wrap-ansi "^2.0.0"

  code-point-at@^1.0.0:
    version "1.1.0"
    resolved "https://registry.yarnpkg.com/code-point-at/-/code-point-at-1.1.0.tgz#0d070b4d043a5bea33a2f1a40e2edb3d9a4ccf77"

  decamelize@^1.1.1:
    version "1.2.0"
    resolved "https://registry.yarnpkg.com/decamelize/-/decamelize-1.2.0.tgz#f6534d15148269b20352e7bee26f501f9a191290"

  [email protected]:
    version "1.1.0"
    resolved "https://registry.yarnpkg.com/doctrine/-/doctrine-1.1.0.tgz#1c36612937cf7d1596b983e9c5d0c6233eeaa3cf"
    dependencies:
      esutils "^1.1.6"
      isarray "0.0.1"

  esutils@^1.1.6:
    version "1.1.6"
    resolved "https://registry.yarnpkg.com/esutils/-/esutils-1.1.6.tgz#c01ccaa9ae4b897c6d0c3e210ae52f3c7a844375"

  [email protected]:
    version "0.2.2"
    resolved "https://registry.yarnpkg.com/file/-/file-0.2.2.tgz#c3dfd8f8cf3535ae455c2b423c2e52635d76b4d3"

  [email protected]:
    version "0.3.0"
    resolved "https://registry.yarnpkg.com/find-parent-dir/-/find-parent-dir-0.3.0.tgz#33c44b429ab2b2f0646299c5f9f718f376ff8d54"

  invert-kv@^1.0.0:
    version "1.0.0"
    resolved "https://registry.yarnpkg.com/invert-kv/-/invert-kv-1.0.0.tgz#104a8e4aaca6d3d8cd157a8ef8bfab2d7a3ffdb6"

  is-fullwidth-code-point@^1.0.0:
    version "1.0.0"
    resolved "https://registry.yarnpkg.com/is-fullwidth-code-point/-/is-fullwidth-code-point-1.0.0.tgz#ef9e31386f031a7f0d643af82fde50c457ef00cb"
    dependencies:
      number-is-nan "^1.0.0"

  [email protected]:
    version "0.0.1"
    resolved "https://registry.yarnpkg.com/isarray/-/isarray-0.0.1.tgz#8a18acfca9a8f4177e09abfc6038939b05d1eedf"

  lcid@^1.0.0:
    version "1.0.0"
    resolved "https://registry.yarnpkg.com/lcid/-/lcid-1.0.0.tgz#308accafa0bc483a3867b4b6f2b9506251d1b835"
    dependencies:
      invert-kv "^1.0.0"

  [email protected]:
    version "4.0.0"
    resolved "https://registry.yarnpkg.com/lodash/-/lodash-4.0.0.tgz#9ac43844c595e28d30108b7ba583703395922dfc"

  [email protected]:
    version "0.3.5"
    resolved "https://registry.yarnpkg.com/marked/-/marked-0.3.5.tgz#4113a15ac5d7bca158a5aae07224587b9fa15b94"

  [email protected]:
    version "0.0.8"
    resolved "https://registry.yarnpkg.com/minimist/-/minimist-0.0.8.tgz#857fcabfc3397d2625b8228262e86aa7a011b05d"

  [email protected]:
    version "0.5.1"
    resolved "https://registry.yarnpkg.com/mkdirp/-/mkdirp-0.5.1.tgz#30057438eac6cf7f8c4767f38648d6697d75c903"
    dependencies:
      minimist "0.0.8"

  modernizr@^3.3.1:
    version "3.3.1"
    resolved "https://registry.yarnpkg.com/modernizr/-/modernizr-3.3.1.tgz#2170b3438a7478c16654324f004802aae6a863e9"
    dependencies:
      doctrine "1.1.0"
      file "0.2.2"
      find-parent-dir "0.3.0"
      lodash "4.0.0"
      marked "0.3.5"
      mkdirp "0.5.1"
      requirejs "2.1.22"
      yargs "3.31.0"

  number-is-nan@^1.0.0:
    version "1.0.1"
    resolved "https://registry.yarnpkg.com/number-is-nan/-/number-is-nan-1.0.1.tgz#097b602b53422a522c1afb8790318336941a011d"

  os-locale@^1.4.0:
    version "1.4.0"
    resolved "https://registry.yarnpkg.com/os-locale/-/os-locale-1.4.0.tgz#20f9f17ae29ed345e8bde583b13d2009803c14d9"
    dependencies:
      lcid "^1.0.0"

  [email protected]:
    version "2.1.22"
    resolved "https://registry.yarnpkg.com/requirejs/-/requirejs-2.1.22.tgz#dd78fd2d34180c0d62c724b5b8aebc0664e0366f"

  string-width@^1.0.1:
    version "1.0.2"
    resolved "https://registry.yarnpkg.com/string-width/-/string-width-1.0.2.tgz#118bdf5b8cdc51a2a7e70d211e07e2b0b9b107d3"
    dependencies:
      code-point-at "^1.0.0"
      is-fullwidth-code-point "^1.0.0"
      strip-ansi "^3.0.0"

  strip-ansi@^3.0.0, strip-ansi@^3.0.1:
    version "3.0.1"
    resolved "https://registry.yarnpkg.com/strip-ansi/-/strip-ansi-3.0.1.tgz#6a385fb8853d952d5ff05d0e8aaf94278dc63dcf"
    dependencies:
      ansi-regex "^2.0.0"

  webcomponentsjs@^1.0.2:
    version "1.0.2"
    resolved "https://registry.yarnpkg.com/webcomponentsjs/-/webcomponentsjs-1.0.2.tgz#b028914c579a61d8144913c7c94c2cf73b95fc69"

  window-size@^0.1.4:
    version "0.1.4"
    resolved "https://registry.yarnpkg.com/window-size/-/window-size-0.1.4.tgz#f8e1aa1ee5a53ec5bf151ffa09742a6ad7697876"

  wrap-ansi@^2.0.0:
    version "2.0.0"
    resolved "https://registry.yarnpkg.com/wrap-ansi/-/wrap-ansi-2.0.0.tgz#7d30f8f873f9a5bbc3a64dabc8d177e071ae426f"
    dependencies:
      string-width "^1.0.1"

  y18n@^3.2.0:
    version "3.2.1"
    resolved "https://registry.yarnpkg.com/y18n/-/y18n-3.2.1.tgz#6d15fba884c08679c0d77e88e7759e811e07fa41"

  [email protected]:
    version "3.31.0"
    resolved "https://registry.yarnpkg.com/yargs/-/yargs-3.31.0.tgz#9f28210aaa0a796570e99505644b968f5e41a1bc"
    dependencies:
      camelcase "^2.0.1"
      cliui "^3.0.3"
      decamelize "^1.1.1"
      os-locale "^1.4.0"
      string-width "^1.0.1"
      window-size "^0.1.4"
      y18n "^3.2.0"

Trace: 
  Error: http://themes.googleusercontent.com/static/fonts/opensans/v6/cJZKeOuBrn4kERxqtaUH3T8E0i7KZn-EPnyo3HZu7kw.woff: invalid tar file
      at Extract.Parse._startEntry (/home/maxw/.nvm/versions/node/v6.9.1/lib/node_modules/yarn/node_modules/tar/lib/parse.js:149:13)
      at Extract.Parse._process (/home/maxw/.nvm/versions/node/v6.9.1/lib/node_modules/yarn/node_modules/tar/lib/parse.js:131:12)
      at BlockStream.<anonymous> (/home/maxw/.nvm/versions/node/v6.9.1/lib/node_modules/yarn/node_modules/tar/lib/parse.js:47:8)
      at emitOne (events.js:96:13)
      at BlockStream.emit (events.js:188:7)
      at BlockStream._emitChunk (/home/maxw/.nvm/versions/node/v6.9.1/lib/node_modules/yarn/node_modules/block-stream/block-stream.js:145:10)
      at BlockStream.write (/home/maxw/.nvm/versions/node/v6.9.1/lib/node_modules/yarn/node_modules/block-stream/block-stream.js:45:10)
      at Extract.Parse.write (/home/maxw/.nvm/versions/node/v6.9.1/lib/node_modules/yarn/node_modules/tar/lib/parse.js:81:23)
      at UnpackStream.ondata (_stream_readable.js:555:20)
      at emitOne (events.js:96:13)