To use a session variable in a Django template, you don’t have to put it inside curly braces like this {{ request.session.variable_name }}.
It is enough to simply write out request.session.variable_name.

Example: You want to use a (custom) session variable inside of an <a> tag using {% url %} to create the correct, well, url. The endpoint however needs some parameters/variables, like for example, company_name.

1<a href="{% url 'session_writer' chosen_slot=slot.start|date:"Y-m-d\TH-i" endpoint="book_treatment" company_name=request.session.company_name %}"  id="{{ slot.start|date:"Y-m-d" }}T{{ slot.start|date:"H-i" }}">{{slot.start|date:"H:i"}} - available</a>

As you can see the variable inside of {% url %} does not need {curly} braces . Variables for other html tags, like id do need {curly} braces.