how to restore Firefox not the last "Restore Previous Session" pages

Question

I would like to restore not the last "Restore Previous Session".

1. Open firefox (v78.0) with few tabs: aaa.com, bbb.com.
2. Close Firefox.
3. Open Firefox, open few tabs, ccc.com, ddd.com.
4. Close Firefox.
5. Open Firefox. How to get those tabs aaa.com, bbb.com from "Restore Previous Session"?

Answer 1

I went to the address bar of Firefox, typed about:support and saw which is the profile folder of Firefox.

I figured out that some versions of Firefox create a c:\Users\MY_USER\AppData\Roaming\Mozilla\Firefox\Profiles\j1hcxbyk.default-release\sessionstore.jsonlz4 file when Firefox is closed.

I also found a copy of a session file c:\Users\MY_USER\AppData\Roaming\Mozilla\Firefox\Profiles\j1hcxbyk.default-release\sessionstore-backups\upgrade.jsonlz4-20200630195452

So, I:

1. stopped Firefox,
2. made a back-up copy of the profile folder,
3. replaced sessionstore.jsonlz4 (or copied there if that file didn't exist) with upgrade.jsonlz4-20200630195452,
4. started Firefox,
5. restored the previous session with: Menu->History->Restore Previous Session,
6. checked that the old session, with my tabs, was restored.

Note: I chose upgrade.jsonlz4-20200630195452 because it was created in the same day, when I closed Firefox with all my tabs.