Function native_formatter_for 

pub fn native_formatter_for(
    model_type_lower: &Option<String>,
    display_name_lower: &str,
) -> Option<PromptFormatter>

Select a native formatter for model families that do not ship a usable HF chat_template.

Inkling is selected only from the authoritative config.json model type; unlike display-name substring matching, this remains stable under --served-model-name aliases. DeepSeek keeps its existing fallback for older model cards that do not publish model_type.