Description of problem: The marketplace is not available with this package. Therefore I am unable to install add-ons for Eclipse. Version-Release number of selected component (if applicable): - 2019-03 (4.11) I don't know what is the name of the base package. I got this information from the About window within the application. The marketplace was present in previous versions of Eclipse and also on Fedora 29.
Closing this. The marketplace is actually in another package called `eclipse-mpc`.