In Ethiopia coffee leaf drinks are called kuti, and also jeno or jenuai. A 2020 review says the leaves were probably Arabica. The published record says little about how kuti is made.
Kuti
The EU safety assessment of coffee leaf infusion used 20 g of dried leaf per litre. Treat it as a starting point to test and note, not as a traditional recipe.
EFSA put dried leaf at about 7 mg caffeine per gram and the 20 g/L drink at 9.9 to 10.9 mg per litre. Leaf and brew vary, so this is one measured case.
The caffeine figure belongs to that assessment. Do not turn it into child, safety or therapeutic claims.
Klingel, Kremer, Gottstein, Rajcic de Rezende, Schwarz and Lachenmeier, A review of coffee by-products including leaf, flower, cherry, husk, silver skin, and spent grounds as novel foods within the European Union, Foods, 2020.
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