To do

• add Source-dependant conversion layer
  • selectable via an optional source kind
  • by default, do nothing
  • if LHAPDF, parse and dump in new format
• convert cached resources
  • when requested:
    • download and
    • save the original one in a temporary location
  • right after (before returning):
    • apply conversion
    • dump new file
    • delete the temporary one
• add a further state in downloading:
  • if resource is present: load and return
  • if present in a temporary location: convert, dump, delete, and return
  • if absent, download
• parse LHAPDF grids
• define new data structure
• de-duplicate/fix YAML during conversion

Later on

• make a dummy registry to run all tests without an internet connection
  • the easiest way is to store a pre-filled cache, that intercepts all requests to the remote