Depending on the project, people may want to configure a Jacoco report by using either .exec file + source files + class files (in the fashion of 1.0.3 release), or by using XML reports they created by themselves to support the corner-cases of their project (in the fashion of 1.0.2 release).
An possible implementation would be to have 2 buttons on configuration page: "Add report based on Jacoco XML reports" and "Add report based on .exec files", so one can choose which report he wants to use.