After upgrading to firefox-bin-96.0 on Gentoo Linux, I found that a number of extensions are malfunctioning. uBlock Origin: 1) Not blocking content. All ads appear. I see this error message in the console: Error: Could not establish connection. Receiving end does not exist. | content_script.js 2) Toolbar icon does not show blocked items count (probably due to above) 3) Clicking toolbar icon causes resulting popup to appear as a vertical line (normal height but just a couple of pixels wide) with no content. 4) Going to Add-on settings and choosing "Preferences" from the add-on's 3-dot menu, the resulting tab crashes. 5) After removing and re-installing the add-on, its button does not appear on the toolbar. 6) After creating a blank profile and installing the add-on, all the above still happens. 7) After downgrading to firefox-bin-95.0.1, all the above still happens. Ghostery: 1) Works on first install (did not previously have this installed); but after restarting Firefox, no longer works. 2) Breakage symptoms similar to uBlock Origin: No blocked items counter (and no blocking). Preferences tab still works though. Multi-Account Containers: 1) Clicking on toolbar icon opens normally-sized but empty popup. 2) Opening a site that's configured to open in a container from a New Tab page tile, the site opens but *not* in the configured container (tab edge is not highlighed in container's colour-code).