What I mean is: when you have n>1 windows, and close one of them, it's a non-event (unless it was last window / last incognito window). You can even revive the closed tab/window (in Firefox even an incognito tab). By default in Firefox you can revive 25 last closed tabs IIRC (configurable).
Window is just a different UI for a tab. Closing a tab drops some resources from memory, but not all / not immediately.
When you close last window, then you close the whole browser, and the story is different. Closing whole browser = dropping all memory, connections etc.
Note in particular: when you have n>1 incognito windows, they share in-memory cache, cookies etc. (Incognito tabs put more restrictions on certain things than normal tabs, for example no disk writes, but unless you close all incognito windows, stuff still lives there in memory).
Yes, what I mean is what happens when you close the last window. I've been surprised to discover over the past year that both Chrome and Firefox sometimes linger in the background. In case of Fx I suspected it's a bug; Chrome on Windows creates a tray icon under some conditions, that remains after all Chrome windows are closed, so I assume it's deliberate.
Do you have chrome://settings/system Continue running background apps when Google Chrome is closed enabled? I see this pref on Linux and Windows, but not Mac. I believe it's enabled by default…
Window is just a different UI for a tab. Closing a tab drops some resources from memory, but not all / not immediately.
When you close last window, then you close the whole browser, and the story is different. Closing whole browser = dropping all memory, connections etc.
Note in particular: when you have n>1 incognito windows, they share in-memory cache, cookies etc. (Incognito tabs put more restrictions on certain things than normal tabs, for example no disk writes, but unless you close all incognito windows, stuff still lives there in memory).