values.yaml contains host: "{{ .Release.Name }}.example.com". What do you write in a template so the output contains the release name instead of the literal braces?

Answer: {{ tpl .Values.host . }}

Explanation

Helm doesn't render values files, so .Values.host is the raw string with the braces in it. The tpl function renders a string as a template with the context you pass, usually the root '.'. include takes the name of a defined template, not template text.