Ribbon Customization setting file ?

When you want to show/hide some Icons from its monitor top line, you are using;

View > Ribbon Customization > "Add" or "Remove" something...

But, I do not know clearly when/why though, the settings are cancelled totally from time to time.
I guess, it happens when I made some modification to my PlugIns members - I have lots of them.

Where can I find the file which has the information I made at "View > Ribbon Customization >..."
I'd like to process the setting file programatically.

Thanks.

[version 2017]