remove references to prd in main README

README.md

@@ -1,18 +1,13 @@
 # PETSIRD template for use cases
 
-The purpose of this repo is to provide a starting point for other software that uses PETSIRD.
+The purpose of this repo is to provide a starting point for developing software that uses PETSIRD.
+It is currently mostly needed/useful for C++ development, but is also useful for Python developers
+who want to experiment with development of PETSIRD itself.
 
 ## Background
 The [Emission Tomography Standardization Initiative (ETSI)](https://etsinitiative.org/)
 is working towards establishing a standard for PET Raw Data, called PETSIRD ("PET ETSI Raw Data").
-
-The specification uses the [yardl](https://aka.ms/yardl) tool to define the model. `yardl` can be
-used to read the specification (in the `model` directory) and generate an PI for both C++ and API to read/write PETSIRD data.
-
-Currently, a draft model is defined in https://github.com/ETSInitiative/PRDdefinition.
-
-CAVEAT: the draft model generates code in the `prd` namespace. Nevertheless, we have used the name PETSIRD here
-in most places (except where needed).
+More information is on https://github.com/ETSInitiative/PETSIRD.
 
 ## How to use this template?