@feqlzma and @wsroboticsizzy, the error was caused by the UCMotor library using the incorrect examples folder name "example". With the regular Arduino IDE this doesn't cause any real problem, and so you will find many Arduino libraries that don't follow this part of the Arduino libraries specification. However, this causes the Arduino Web Editor to think the UCMotor.zip file you provided contains sketches, not a library. So it happily imports the library's example sketches, while ignoring the library. The solution is to simply rename the example folder to the correct name: examples. I have attached a UCMotor.zip file with the problem corrected in case you don't feel like making this change yourself.
So I think the error you encountered has nothing to do with the original bug reported in this thread.
This is likely to be a fairly common problem so perhaps the Arduino developers might look at how the import's library detection can be improved. In a recent automated scan of 8737 unique (not development forks) Arduino libraries on GitHub, my script detected that 345 had an incorrect examples folder name.
UCMotor.zip (74.6 KB)