I have it as a Phenidone equivalent of ID-3 (similar to Selectol Soft/D165) it's adjusted to make 1 litre:

Example 1

Phenidone 6 gm.
Sodium sulphite (anhyd.) 25 gm.
Sodium carbonate (anhyd.) 37.5 gm.
Potassium Bromide 1gm.
Water to make 1 litre

To use 1+3

Results are similar in characteristics to a Metol only developer using the same weight of developer,
only softer.

It's unusual as it has a very high level of Phenidone unlike the usual substitutions.

All the examples in the Patent are Phenidone substitutions for Metol in existing Metol or MQ formulae, so ones a Phenidone/Pyrogallol developer.

Ian