kDrive 3.3.7 for Mac could be downloaded from the developer's website when we last checked. We cannot confirm if there is a free download of this app available. The application is included in Productivity Tools. 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. The actual developer of this software for Mac is Infomaniak.
From the developer:
kDrive is a modern, privacy-friendly application that lets you edit, share, and access all your data with ease. It allows you to edit documents, spreadsheets, and presentations online; collaborate in real time on Word, Excel, and PowerPoint files; easily share the files and folders of your choice, and even recover an old version of your files.
You may want to check out more Mac applications, such as PDFMergeThing, Apimac Clean Text or Gordon, which might be similar to kDrive.