To be honest, I think the provided suggestion of how to do this is a bad idea in that these changes will be lost when you upgrade, so bear that in mind. Development is a very particular mode that lets you change things that we intentionally don't expose in "normal" operation.
Well it may expose some things that you shouldn't be editing unless you understand the significance. There are a number of things we don't expose specifically because they're part of the "master" XF data and thus your changes will be overwritten when you upgrade.
Beyond that, yes, there is information that debug mode may leak which can have security implications.