Mutes new tabs until you un-mute them
Mute New Tabs stops websites from making noise without your permission. It uses Chrome's tab muting API to automatically mute new tabs. On supported sites, it automatically unmutes the tab when you interact with an in-page volume control. If needed, you can un-mute a tab by using the context menu on the tab itself.
Note: to restore the "Unmute tab" and "Mute tab" context menu actions, disable "Sound content setting" in chrome://flags.
This extension also
1) mutes tabs on startup, because Chrome doesn't remember which tabs were muted.
2) mutes the tab when you navigate to a different origin.
All behaviors can be toggled in the extension's popup window.
This extension does not include any kind of analytics or tracking.
Why it uses these permissions:
"Read and change your data on a number of websites" - inject content script that sends "unmute" message to extension when you click an in-page volume control
"Communicate with cooperating websites" - receive "unmute" message from injected script
"Read your browsing history" - determine if a tab moved to a different domain (origin)
Mute New Tabs can also be installed from source: https://github.com/ludios/mute-new-tabs