A custom template tag is an application-defined template instruction that performs an operation during template rendering. Django treats tags as pluggable components, so templates can gain behavior beyond the built-in vocabulary. section 14.1
Use one when a repeated presentation task belongs in the template layer. Django provides shortcut mechanisms for some tag types, allowing small custom tags without building a large extension. section 14.1
Inline conditional output
The Django Awl library includes {% qif %}, an inline-if tag for conditional content when a full template block would take too much space. section 14.1
