Okay, I have about a dozen different recipes.
Basically it's oil, tallow and wax with a colourant added.
Some recipes call for soft soap and some for treacle or syrup

and most seem to add Myrbane (nitrobenzene) to the mix........that's probably as a preservative, some of my old cosmetic recipes used benzoin to do the same job.
How about this one, simple as I can find.
Light mineral oil 5 parts
Tallow 2 parts
Paraffin wax 1 part
these are melted together in a bain marie then a little lamp or bone black (just carbon) is added and mixed in well. As the mixture is cooling add in a few drops of Myrbane or Benzoin essential oil and stir well.
If you really want the other recipes I could scan them and send to you, but they've got masses of fish oils, one's even got whale oil
Looking through the recipes there's another kind that seems to be for a hard shine (military boots ?

) that one's made by using powder roisin in the mix. It's rubbed well into the leather and allowed to sit for a little while and them buffs up to a high shine.
Hope this helps,
cheers,
Mary