The publication system enables users to write their own templates. This has been used rather rarely and requires several security considerations to be made (white lists, separate domains to use the sandboxing features of javascript...). It also prevents the updates of templates to reach users, as a template is cloned into the user folder the first time a publication is created.

com.openexchange.templating.usertemplating = false

This toggle is set to false as default, which disables user templating.

Potential side effects: This will disable user templating for all customers, even if previously used, as this property was never set before, so the default will apply to everyone.
Second, probably beneficial side-effect: Updates to templates on the server side now reach customers.