Requested by jschulte
On https://documentation.magnolia-cms.com/display/DOCS56/How+to+get+content+as+JSON+-+an+overview#HowtogetcontentasJSON-anoverview-FreeMarkertemplate
Add the template variant mechanism approach. Namely that you can have multiple freemarker variants: one for html, one for json, etc.
The benefits are that you get proper preview and you don't need multiple templates.
See the files from Jan attached.

Also improve the content about variations on https://documentation.magnolia-cms.com/display/DOCS56/Template+definition