An early game mod with new primitive devices, combustion machines, smelting mechanics, storage options, tools, torches, advancements, and absolutely zero GUIs -- with exception to the substantially complete, mostly illustrated, and charred guidebook.
Once upon a time in Russia (and much of eastern Europe) it was not uncommon to soak leather in wood tar to strengthen it and make it more resistant to strain and impact.
If this would be useful as a material in and of itself I could see it being used for advanced bags, however my primary suggestion is that soaking leather armor be used to add unbreaking 1 to the leather armor pieces.
Once upon a time in Russia (and much of eastern Europe) it was not uncommon to soak leather in wood tar to strengthen it and make it more resistant to strain and impact.
If this would be useful as a material in and of itself I could see it being used for advanced bags, however my primary suggestion is that soaking leather armor be used to add unbreaking 1 to the leather armor pieces.