What is the general goal of the feature?
To provide a simple and intuitive way for a user to add another group if they are not working in a purely linear fashion.
With repeat groups the only way I can see to add a new group is to navigate to the last question in the group and then try to go past it (to trigger the 'Add New Group' dialogue).
For me it would be really great to have a button for 'Add New Group' in the Jump Menu / 'list view' of questions if I am within a repeat group. I have had trouble explaining this to users who are not yet proficient with ODK 'logic'.
In my case the fact that ODK can be used in a not-entirely-linear fashion is a great bonus, and skipping around the form is essential for adding information as it arises in a survey in the field, but that means that the user needs to remember to go to the last question of the repeat in order to add a new group, which doesn't match the simplicity and power of the Jump Menu / 'list view'.
There is already a button 'go up' when in this Jump Menu / list view, so replacing 'Go to End' with 'Add Group' in this scenario might be more logical? So if the recorder actually wants to 'Go to End' (i.e. save and exit) whilst within a repeat group he/she needs to 'Go up' first? That would also safeguard against missing questions that are in the main form but after the repeat group (without making them 'required')... It would reinforce the concept of repeat groups being 'nested' within a main form (e.g. subsets of linked data).
What are some example use cases for this feature?
Any form with repeat groups where there might be a need to skip around the form (i.e. using the excellent existing functionality!)
What can you contribute to making this feature a reality?
Not really in my field of competence, sorry.