Retrieving content from non-registered macros

Hi everyone,

after migrating to Xwiki from Confluence and using Pro Macros, there still is a macro that doesnt get converted. The Confluence macro is a simple textbox.
Through using Pro MAcros I realized that the information should still be there and is simply not displayed. Before using Pro Macros I was gettin these error messages about non-registered macros on most pages. With Pro Macros the content is show correctly, so I guess that the text has been implemented.

So the question is if I can somehow access the text that is supposed to be shown by ui-text-box. That would speed up the manual conversion by a lot.

Thank you very much.