Changes
avoid passing {{{content}}} through, as subtemplates only need to know if it is blank or not, per protected edit request
| heading = {{{heading|¬}}} <!--Empty but defined means no header-->
| heading-style = {{{heading-style|}}}
| content = {{#if:{{{content|}}}|1}}
<!--Some namespaces must have the /doc, /sandbox and /testcases
-->{{documentation/end box2
| preload = {{{preload|}}} <!--Allow custom preloads-->
| content = {{#if:{{{content|}}}|1}}
| link box = {{{link box|}}} <!--So "link box=off" works-->