Oracle SQL 11gR2 => retrieves all data where "impdp" was executed

Hello, my team has done several databases Data pump import "impdp" in the last two years.

The workflow has always been to import all "application schemas" (the schemas used by our application). daily backup 2019-04-05.sql Dump one of the daily backups.

Now I have to find out the exact dates "Impdp"Restore where performed.

I tried the following:
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I found the file dpdump on my server, but it only contains these three lines:

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I only have on "import.log" file, which was overwritten with each restore dpdump was taken.

Are there any system tables where I can check each time, when dpdump was carried out

Where else can I search for "log files" for the protocol?