Would there be any point to this unless the paper obtained the documents themselves.
The paper is not likely to reveal their source without a long court battle and they may not know who the source is.
Regardless if the source feels threatened he may make the documents available to all comers on the internet.
The documents pertain to an Indian submarine programme, so it , in one sense, doesn’t affect Australia.
The same company has won a much larger contract to build new submarines for Australia. The bigger issue at play here is the information security that DCNS provides for the Aussie programme.