According to this page of the Apache ISIS documentation, one can configure own images for brandLogoHeader and brandLogoSignin. However, the Alt-Attribute of the resulting img-Elements default to the value Brand. I'd like to not just adjust the images but their Alt-Attribute, too. But how? Haven't found anything in the documentation yet.
There is no way to do that with configuration. One way is to configure custom component for the header panel. Another way is to set it with JavaScript on page load/domready.
Please start a discussion in our mailing lists if you think this deserves a configuration setting.