The biggest sticking point is that the new map isn’t compatible. Unfortunately, bringing the mapgen-era map back, even as a separate thing, would pose security risks.
dat .dat though
The good news is, we don’t need it anyway. A few old .html files exist for older galaxies, and we can use those as a reference point to figure out how to compose the .dat files for current galaxies. No live version of the old map needed.
Even better, I found a post and some code from Smartys that may be a big enough hint to get us started:
Humorously, he made this comment about Stefan hosting his file:
We may see it just yet.
I’ll post here when I have more info.
The in-game map will still ultimately aim to replace mapgen entirely. Until then though, if we can support it, we should.