When I try the command: "git fork https://github.com/openjdk/jdk" I get:

# git fork https://github.com/openjdk/jdk
Username for 'https://github.com': gerard-ziemski
Password for 'https://gerard-ziemski@github.com':
Sep 14, 2020 11:31:00 AM org.openjdk.skara.network.RestRequest transformBadResponse
WARNING: org.openjdk.skara.network.RestRequest$QueryBuilder@6b9651f3
Sep 14, 2020 11:31:00 AM org.openjdk.skara.network.RestRequest transformBadResponse
WARNING: {"message":"Bad credentials","documentation_url":"https://docs.github.com/rest"}
Exception in thread "main" java.lang.RuntimeException: Request returned bad status: 401
at org.openjdk.skara.network/org.openjdk.skara.network.RestRequest.transformBadResponse(RestRequest.java:285)
at org.openjdk.skara.network/org.openjdk.skara.network.RestRequest.execute(RestRequest.java:358)
at org.openjdk.skara.network/org.openjdk.skara.network.RestRequest$QueryBuilder.execute(RestRequest.java:156)
at org.openjdk.skara.forge/org.openjdk.skara.forge.github.GitHubRepository.fork(GitHubRepository.java:239)
at org.openjdk.skara.cli/org.openjdk.skara.cli.GitFork.main(GitFork.java:284)
at org.openjdk.skara.cli/org.openjdk.skara.cli.GitSkara.main(GitSkara.java:230)

I am assuming, by looking at the output, that the username/password combo is wrong (though why that is is a different issue), but we should be catching such scenario and printing a helpful message pointing the user to what to check for and suggest on how to fix it.