This is the core question. Autodesk now distributes Autodesk Manufacturing Data Exchange Utility (the successor to PS-Exchange).
Since "3407" is not a standard public version number (PS Exchange versions typically follow years, like 2018, 2019, or build numbers like 6.x), it is highly likely that generated during a file conversion process. delcam ps exchange 3407 link
This content is for informational purposes. "Delcam" is a trademark of Autodesk. Always ensure you are complying with software licensing agreements when installing legacy software. This is the core question