The TensorFlow.js project has its own repository to collect machine learning models that are compatible with the latest in TensorFlow.js. The repository is named tfjs-models: https://github.com/tensorflow/tfjs-models.
These models are pre-trained and uploaded in npm, unpkg, or jsDelivr so that we can quickly use the model in our application. As you may already know, npm is a package manager for the Node.js environment. It is easy to install the model in your Node.js application by using the npm or yarn CLI. For web applications, unpkg is a good option. It is an open source project providing a global CDN that is designed to serve every npm package. tfjs-models and TensorFlow.js core are served via unpkg. jsDelivr is a similar application that serves static content on our behalf.