Hello. Anytime a JSON contentmodel page is saved, it's being autoformatted. The result is extremelly huge, because all the indentation is made by spaces. I suggest to replace it with tabs, so the redundant part will shrink in four times.
For example, from a small 103-kB file: a short piece
{ "stations": [ { "number": 1, "x": 1036, "y": 771, ...
has 48 spaces, which can be replaced with 12 tabs. Thank you.