This message is displayed when repairing a tool using the Tinkertool. It's incorrect, however. It displays the new amount of repair it has (e.g. 90/100 = 90%) instead of the amount by which it was repaired. When repairing my non-broken Grinder, it keeps telling me things like "You repaired by 50 percent" when I repair from 35/100 to 50/100.