AutoPause

Browser extension to pause other audio and video sources if audio is playing on the active tab with automatic resume, fast forward and media controls.

Chrome listing: https://chrome.google.com/webstore/detail/autopause/bcecldolamfbkgokgpnlpmhjcijglhll
Firefox listing: https://addons.mozilla.org/firefox/addon/autopause/

Security

If you believe you have found a security vulnerability, please report it responsibly. You can refer to the security.txt file for contact information or open an issue on the GitHub repository if you prefer (though for sensitive vulnerabilities, direct contact is encouraged).

How do I know the webstore version is the same code?

https://github.com/NDevTK/ExtensionTransparency

Should the owner ever release a Chrome version without Firefox support

NO THEY SHOULD NOT.