Might we request a license be added to this and MapWriter so that myself or others can port these to newer versions of Minecraft.

Without a license we can't port this or publish it to CurseForge (the new mod launcher/distributor modders and players use now to play modpacks and share mods) and maintain it without it breaking licenses and such.

https://choosealicense.com/

Hope you are well and that we hear back soon so that we can bring back this great old mod!

using index.html i am unable to see the negative half of the map.
I was able to work around this issue by essentially shifting the map and adjusting the coordinates.

To do this, i adjusted three lines. adding a value of '128' to all of them.

offset new markers
position: new google.maps.LatLng(y / 512, (x / 512) + 128),

offset the starting position
center: new google.maps.LatLng(0, 128),,

offset the image to load
return 'overworld (dimension 0)/images/z' + z + '/' + ((coord.x-(128*z))) + ',' + coord.y + '.png';

Any chance you could update it to support the 1.7.10 block/biomes to 1.7.10?