Zen, at least from the few times that I've tried it, also has some major issues that I personally find to be deal-breakers. Like forgetting tabs in a window that has just been closed. If you accidentally close a window that you're working, without quitting the browser, you lose everything in it. As someone who is prone to doing that when closing a tab, it's not ideal.

Thanks! Sounds like limiting risk from the California bill is a plausible reason, but it isn't confirmed.

Legal Definitions of "Selling Data" Under the CCPA Are Broad: As noted above, the CCPA's definition encompasses many data-sharing practices that may not align with common understanding of "selling data".[16] Even if Mozilla was not directly selling user data, its search partnerships, telemetry data sharing, & sponsored content could have been interpreted as data sales if Mozilla received any financial benefit from them, all of which were actions that Mozilla has already been transparent & upfront about.

Mozilla's Search Engine Deals Could Be Considered Data Sales: As mentioned earlier, these partnerships could legally qualify as data sales under the CCPA definition, despite being an existing part of Mozilla's business model that consumers are already aware of.[1]

Sponsored Content in Firefox's New Tab Page Involves Data Exchange: Mozilla dReferencesisplays sponsored content and ads on the Firefox New Tab page, which may involve user interaction data being shared with advertisers.[11] Even if the data is anonymized, the CCPA considers certain types of aggregated data as personal information if it can be linked back to users.[16]