Sorry for AI but I couldn't find it by just googling:
Yes, Firefox did have an in-house developed "Tab Center" — it was an experimental feature created by Mozilla as part of their Test Pilot programme around 2016–2017.
🧪 Mozilla's Original "Tab Center" Name: Tab Center
Status: Experimental Test Pilot feature (now discontinued)
Timeframe: Circa 2016–2017
Purpose: To explore the usability of vertical tabs on the left side of the browser, instead of the traditional horizontal layout.
🔍 Key Features Displayed open tabs vertically in a sidebar.
Showed a more spacious, scrollable list of tabs.
Included favicons and tab titles — easier to manage lots of tabs.
Supported mouse gestures like tab pinning and closing.
Looked and felt very similar to Edge’s modern vertical tabs.
Some Chinese EVs copy the style of fancy cars. For example the Xiaomi EV practically ripped off a Porsche.
Original, high quality designs require high development costs. Also a good design should consider the functionality as well, such as aerodynamics specific to the power and handling of the vehicle. Weight distribution etc.
Edit: not an expert at all, just my guess and observations