I need some clarifications regarding the customization of this report.

I tried hard to add columns to reflect some fields from the journal entries.

However, I noticed two issues:

1. You cannot use fields added through Odoo Studio, which is disappointing.
2. Not all core fields can be added; some work while others do not, for unknown reasons.
3. The fields that worked were of type Char or Selection.

The reason for this modification is to display the exchange rate used in the journal entry.