I want to list all the saved searches which are modified (action=edit) from the logs, but the exact search string is not visible in the logs. Can some one guide me on how to approach this one?
I believe the search string is not logged on edit, consider using version control.
It might not fully answer your question but I think it's a good start if you take a look at my answers here:
It was a very long discussion on how to list saved searches and who has been and hasn't been using them in the last two months.
It contains the search string you are looking for.