You can hide the secondary line that shows the Playing and Muted state as text labels by modifying the <b>browser.tabs.secondaryTextUnsupportedLocales</b> pref on the <b>about:config</b> page and add your language to the list. For "en-US" this would be "en" (i.e. the part before a possible '-'): *ar,bn,bo,ckb,fa,gu,he,hi,ja,km,kn,ko,lo,mr,my,ne,pa,si,ta,te,th,ur,zh,en You can open the <b>about:config</b> page via the location/address bar. On the warning page, you can click "Accept the Risk and Continue" to open about:config. *https://support.mozilla.org/en-US/kb/about-config-editor-firefox

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