CoreHacks are the next step after EasyHacks on your journey to become a core developer. They require more time and require often that you spend some time researching the best technical solution. You'll still have a mentor that might help you answer some questions. If you have never done any LibreOffice development, please start with an EasyHacks.
If you plan to work on a task, add yourself below the project and talk to the mentor.
Currently LibreOffice supports OOXML transitional import and export and initial OOXML strict import. We should however work on supporting OOXML strict as well during export and fix some of the import problems that will be discovered during the export work.
The biggest difference between OOXML transitional and OOXML strict are different namespaces and different URLs in relationships. For the import I managed to abstract them a bit but they are still mostly string based. We should switch to an enum based approach for most of them that is translated in oox/ to the URL. Additionally all content that is in OOXML transitional but not in OOXML strict needs to be guarded by a check.
Mentor: Markus Mohrhard, moggi, firstname.lastname@example.org
Please make sure that the task you are going to add is feasible and can be solved by someone who has an intermediate understanding of the code base. The project can require some research if you add some pointers showing where to look for information.