In a file manager, integration with the system is important, which means that a dozen or two integration features should be implemented for each platform, aside

In a file manager, integration with the system is important, which means that a dozen or two integration features should be implemented for each platform, aside from the internal differences in working with files. And that Electron is likely out. In addition, a file manager is pretty much a productivity app, so it has to be muscle-memory-level fast. For desktop software recommendations in established genres, AlternativeTo is a good source: https://alternativeto.net/software/windows-explorer/ https://alternativeto.net/software/windows-explorer/ But alas, there doesn't seem to be anything cross-platform of this sort there. Double Commander enjoys popularity and is cross-platform, but dunno how it feels on Windows. On Mac, it's decent though hasn't got much in the aforementioned integration department.