The upgrade reports the entities have been migrated to the UI.
Now each entity is duplicated.
I delete my yaml entries and restart HA.
The File integration vanishes and I have no file entities.
So, I add the integration and create a file entity in the integration’s UI.
It creates an entity called sensor.file ! I use the UI to rename the entity.
Ok, I have a way forward but have to delete the other entities now visible in the entity list that were created and then lost by the file integration.