LiveView 1.0 introduced new HEEX syntax which allows interpolation with brackets in HTML body, see sigil_h docs. The current TailwindFormatter uses engines and tokenizer code copied from LiveView version 0.20.1. If you run mix format --check-formatted on a Phoenix LiveView 1.0 project, it will return an error.

I copied over the equivalent code from LiveView 1.0.9, and mix format --check-formatted is successful in my project. I can open up a PR with those changes, but I was wondering if you planned to continue with that approach and how it would work with your project versioning.