The feature was a letter generator. Somebody fills in a few fields and gets a finished letter of recommendation, resignation letter or notice letter, in plain text, ready to paste into an email. The obvious build is a prompt and a model call.
Source: [Dev.to](https://dev.to/thedolceway/i-removed-the-llm-call-and-replaced-it-with-200-lines-of-template-code-2lh0)