What's the meaning of an AWS Glue Database name in italic?

I have a Glue job that writes to a table. If I do this and pointing to a “non-italic” database, the table is shown afters in the table view. If I let the Glue Job write into the “italic” database, then the table is successfully written, too, but not listed in the table view.

Furthermore, I can see both the newly created tables in Athena in the table list and I can do querying over both. If I create a new Glue Job, I also can see both table in the source data catalog table dropdown. I.e., I can see the table in the “italic” database everywhere but not in the table view.

Is the “italic” database some kind of shared database or so? What's the meaning of it?