MP3 Diags
In the Config - Others tab you can see in the middle of the window a "Misc" group. Inside it there are 2 checkboxes that allow you to add to the main window's toolbar two buttons that are invisible by default: "Debug" and "Sessions".
The "Debug" button opens up a new window where you can export song information to a text file or see trace messages from the last file scan (as long as you didn't close the application, because these are not stored on the disk, and provided that logging is enabled.)

Another option that you can configure here is logging all the changes to a file. The log file is located in the same directory as the ".ini" session file
The "Sessions" button should be more interesting. It allows you to keep several separated sets of folders containing MP3s, each set with its own settings. Everything that you see in the configuration dialog is stored "per session". Once the button is visible, you can click on it to see the "Sessions dialog", where you can add / remove / change sessions. Note that if you spent some time getting the settings right, you may want to use the "Save as ..." button, which will copy your settings to a new session.