Web add-In: how to download base64 encoded content in outlook on mac?

Question

I want to implement a web add-in feature to download base64 encoded data. This works for OWA and windows client, but does not work in outlook on mac.

Can you explain how to download any base64 encoded data in outlook on mac?

Tested variants

FileSave.js

   <IconButton  
     iconProps={<!-- -->{ iconName: 'Download' }}  
     onClick={() => {  
       FileSaver.saveAs(data, filename);  
     }}  
   />  

Works on windows and OWA, but not in outlook on mac.

Object URL with Link

   <a href={URL.createObjectURL(blobObject)} download={filename}>download</a>  

Works on windows and OWA, but not in outlook on mac.

Data URL with Link

   <a href={`data:;base64,${data}`} download={filename}>download</a>  

Works on windows and OWA, but not in outlook on mac.

openBrowserWindow

I also tried to open a browser windown containing a data url

   Office.context.ui.openBrowserWindow(`data:;base64,${data}`)  

or a url created by URL.createObjectURL()

   Office.context.ui.openBrowserWindow(`blob:https://localhost:3000/<uuid>`)  

URL.createObjectURL() should not work, because if the use defined an other default browser than safari, this link is invalid.

Additionally openBrowserWindow() only works with urls starting with http:// or https://. URLs starting with data: or blob: are not recognized and does not open a new new browser window.