Template expansion

When you use the template module, where does it do all the jinjaness
(variable expansion, loop, etc): in the host you are running ansible
from (server?) or the one you are applying it to (client)?

The *template* is completed at the controller. In fact, the modules
*stat* and *file* are used behind the scene to write the file at the
client.

Short answer would be: Is Jinja package needed at the client?