%str2json
%json_add
%json_remove
From those requests: - https://forum.plantuml.net/15436/allow-update-json-object-or-array-value - https://forum.plantuml.net/17474/modify-json-variables-in-preprocessor - https://forum.plantuml.net/18418/request-%25set_json_keys-function-json-writing-capabilities - #328 - #1733