Google has removed an extension from Chromium, the open-source sibling of the Google Chrome browser, after privacy activists alleged that the extension allowed the search giant to spy on users. The software uses a computer's microphone to listen for the “Ok, Google” phrase, which triggers voice searches.

Open-source developers and privacy activists complained that Chromium was automatically downloading the “Chrome Hotword” extension, giving users no advance warning and making it impossible to stop the download. While Hotword was turned off by default, both Google Chrome and Chromium (if set to default browser) can permanently listen to a user's microphone, with “Ok, Google” set as the trigger word, according to Ars Technica.

“Without consent, Google's code had downloaded a black box of code that – according to itself – had turned on the microphone and was actively listening to your room,” Rick Falkvinge, founder of the Swedish Pirate Party, said in a blog post last week. “Which means that your computer had been stealth configured to send what was being said in your room to somebody else, to a private company in another country, without your consent or knowledge, an audio transmission triggered by... an unknown and unverifiable set of conditions.”

But not anymore. Google explained on its product pages that the “black box” will not be installed unless a user manually adds it from the Chrome Web Store, then enables the voice-search option.

“As of the newly landed r335874 Chromium builds, by default, will not download this module at all,” one developer explained. “Chromium is open source and it's important to us, as it is to you, that it doesn't ship with closed-source components, lazily or not.”