I inspected the jar and I realized that it is not JSON's fault.
There are three reasons the footprint grow:
1-I loaded images inside the theme.res (964kb)
I loaded 512px images and CN1 created the derived ones I guess, but are they created before installing? Should not they be created in the app folder at installation time?
2-I found a file that is not found in the project, I do not see it: white_container_theme.res (594kb). It was created some time ago but I think it is not used anywhere. In fact it is neither seen in the project structure nor inside the theme.res itself, still it is in the jar (?) I also searched the occurrence in the project but it is not found.
3-The html folder is duplicated (170Kb)
I do not know if the limit would not be exceeded but each point is worth understanding.