Webful PasswordMaker is a modern app providing an interface for the PasswordMaker protocols supported by various browser extensions on desktop and some older mobile apps.
The app can create per-site passwords deterministically, securely and offline. And it now supports multiple profiles to help fulfil web sites varying password requirements. Its source is available on GitHub, and all cryptographic functions use trusted 3rd-party libraries to reduce the chance of introducing vulnerabilities.
The conventions followed for the hash protocols are detailed at https://passwordmaker.org/