Tested on IE and Chrome. Tested logged on and not logged on. Same error during download from the Eclipse Marketplace.
https://marketplace.eclipse.org/content/bash-editor#comment-5548

HTTP Proxy Authentication Required: https://dl.bintray.com/de-jcup/basheditor/content.xml
Proxy Authentication Required