Alternatively, Anki could export its data into the txt file, in pretty simple format, and then it would take just a couple of lines of code in modern scripting languages to convert such txt file to DSL format.
Personally, for me the flow of information is *always* one-way, from GoldenDict to Anki, and I have never had any need to move my Anki data (which originated from Goldendict dictionaries) back to Goldendict.