I recently built an open-source tool that automatically converts Chrome extensions to Firefox extensions.

It uses Rust and AST-based transformations (via SWC) instead of simple string replacements, so it handles Manifest V3 extensions more reliably than older approaches.

You can check it out here:
https://github.com/OtsoBear/chrome2moz

Might be useful for anyone still looking for a practical Chrome → Firefox converter. Feedback and contributions are welcome.