Download of FreeSpaceFile X 1.0 for Mac was on the developer's website when we last checked. We cannot confirm if there is a free download of this app available.
Please check the Mac app with an antivirus before launch as it is downloaded from the developer's website, and we cannot ensure that it is safe. This free Mac app is a product of Camp Software. The software lies within System Tools, more precisely File Managers.
From the developer:
FreeSpaceFile saves a text file whose name tells you how much free space is available on the volume. This is useful if you are accessing files on a server where you cannot perform a get info like with FTP or Hotline servers.
You may want to check out more software for Mac, such as pdf-FieldMerge, which might be related to FreeSpaceFile X.