It would be good to implement something like this, similar to Microsoft Edge. This would help to decrease the amount of time it takes for Firefox to start up.
I don't want any fake quickstart features which just hide loading during the system boot process. This makes booting slower and brings background processes sitting around all the time. This is a resource hog and not desireable in terms of minimizing attack surface for security reasons.
The only proper way to make Firefox start faster is to optimize the process for efficiency or make it more slender.
Wouldn't you guys like a Fast Startup feature for Firefox?
What the feature should do: It basically preloads Firefox on Windows Startup. Thats all. If you open Firefox it'll start very much faster. Maybe you know that concept already from Microsoft Edge, I think they call it Startup-Boost.
Huh, for me Firefox already starts in the matter of seconds.. Either completely or firstly the empty-loading mockup, then completely. All takes like 3 seconds or so.. I don't know whether it's the Superfetch (browser is like the most used app on my PC), the fact that I keep my startup list clean of apps like steam, messengers, spotifies, etc or the system drive being on an SSD (not NVMe btw, almost entry level one), but I don't remember such problems as slow Firefox startup.
Edit: Checked it now, rebooted my laptop, clicked the Firefox on the toolbar, launched in a second. Though I admit that my laptop may have specs above average even for a 5-year-old.