Purpose of bump on old pocket knife?

While cleaning out a deceased family member’s house I came across these two knives. Any idea what the purpose of the “bump” on the back of the blade is for?

hso said:

View attachment 1018583
Grafting knife. The "bump" is for removing bark.

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Thanks. I had a feeling you might know; I asked a few knife friends locally and no one had a clue. We were guessing it may be for cleaning a horse hoof.

Grafting makes a lot of sense as he was very big into roses and had several rose show trophies in the house.