mmap to xls conversion is actually often done not as file conversion, but import of the mind maps to MS Excel worksheets. Typically used for various diagrams or structures, but might be even whole mind maps.
What is done that these are exported as pictures that are then imported as objects to Excel. Some mind mapping software offer direct linking between the map and file, so it works dynamically.
In case of MMAP maps, these come from MindManager, but other similar tools can be used same way, provided these support .mmap files as well.
Updated: September 28, 2023