{$node.object.contentclass_id}
or
{$node.object.content_class.id}
or identifier {$node.object.content_class.identifier}
You can also use fetch functions related to class
http://ez.no/doc/ez_publish/technical_manual/4_0/reference/modules/content/fetch_functions/class http://ez.no/doc/ez_publish/technical_manual/4_0/reference/modules/class
Avoid the two last examples unless you need to fetch the entire content class object ($node.object.content_class).
Yup,
That's why smart structure planning may take care of site optimization at the same time, when you only display object names and other pre-fetched pieces of data rather than reach into data_map for your lists generation.
data_map is prefetched (all attributes on all fetched nodes in one sql call) in content tree and content list fetches, this is controllable with the load_data_map fetch parameter from 3.10 and up so you can disable it if you don't use the data_map on the fetched node set.
Ok, I must have been thinking of PHP-object-level when I was writing that, and there I need to call for data_map explicitly.
But I hadn't known about that load_data_map fetch feature - interesting. Not working with tpls much... ;)
Thanks, Piotrek