How are recovery files named (what extension)?

I lost some work in calc and by mistake I clicked discard recovery files.

After googling, I’ve found that locations should be ~/.config/libreoffice/4/user/backup and maybe ~/.config/libreoffice/4/user/temp.
Both are empty.

I have recovered all data from my /home partition using photorec. There is tons of stuff, now I need to find what extension do these recovery files have?

This question has already been covered many times here. Search above for the word “recovery”.

See [Tutorial] How to recover corrupted, broken, lost or deleted files, and those with #####

If this helps then please tick the answer and/or show you like it with an uptick.

It doesn’t really help. Like I said in question I have looked in those folders and they are empty. I have recovered entire home folder and it’s huge without indicator of what folder the files were in. It is not what I asked for. I just need to know the extension.

If you read it you will see it tells you what the backup, AutoRecovery and temporary files are named with their extensions, and exactly where they are located. It is based on Writer but will be the same for Calc.