Currently, via the web tooling, there is no way to view or delete counterexamples in the WA workspace. You may add them using the "Irrelevant" tag in the "try it out" panel, but after that the counterexample is not easily inspect-able.
This causes problems in client's workspaces that utilize this feature, like GEICO, or MBFS, since there may be conflicting training in the counter examples and the intent training, and you can not realize this unless you download the json object and inspect it. that way.
I'd recommend that that counterexamples be available to inspection, and modification in the UI and also have an import/export mechanism that allows for utf-8 csv files to be the source of the information.