A recent refactor (rFfb89658530da25a77dc03fb329c394198bf6358f) performed on Linux didn't properly update a Windows-only file.
os.IsNotExist()
errors.Is(err, fs.ErrNotExist()
`os.IsNotExist()` is from before `errors.Is()` existed. The latter is the recommended approach, as it also recognised wrapped errors. No functional changes, except for recognising more cases of "does not exist" errors as such.
`blender-launcher.exe` doesn't pipe Blender's stdout/stderr output, so it's not useful for Flamenco.