Shrinkray: Lightweight alternative to Electron
github.com
github.com
In my experience, projects that are OSX first often work horribly on other platforms (the poster child being itunes). Hence I switched to Visual Studio Code the second it became available.
[1] they gave you build instructions for linux & windows. Which almost never worked.
And I have to agree with other commenters that this will only truly be an alternative if it could be cross-platform. It seems cross-platform support is possible (by using each OS's own browser runtime), but then you'd have discrepancies between platforms which takes us back to square one.