FileMaker Pro supports both the import and export of Excel spreadsheets, so it may be well possible to export even old FileMaker databases like .fp5 files XLS spreadsheet format. Of course this will only work if the the latest versions of FileMaker still support its own old database formats.
Convert FileMaker Pro database file to Microsoft Excel 97 to 2003 workbook.
We found 2 software records in the database related to .fp5 to .xls file format conversion.
Microsoft Windows software - convert fp5 to xls on Windows
A program used to create and manage information databases
Convert from fp5 file format
The tables with software actions are a good pointer for what a certain program does with various file types and often may give users a good hint how to perform certain file conversion, for example the above-mentioned fp5 to xls. However, it is not perfect and sometimes can show results which are not really usable because of how certain programs work with files and the possible conversion is thus actually not possible at all.
Apple macOS / Mac OS X software - convert fp5 to xls on OS X
A database management program for Mac