That was close…
I just finished writing and editing the previous post, when Firefox crashed.
You can imagine I stopped breathing for a couple of minutes. Surprisingly, restarting it launched the “Create Post” page with the entire text in it. I don’t know if I should thank Firefox, or SessionSaver (without whom Firefox would’ve started with the homepage), but whoever is responsible for this, you have my eternal gratitude, for what its worth ;).
(Update: turns out it wasn’t lost, but managed to post before the browser crashed.)