A lot of material has accumulated here which should be moved elsewhere. Projects that have been completed and adopted into stock DSpace should move to their appropriate areas in the Official Documentation alongside similar features. We should have (if we do not already) an official section on "extending DSpace" in which notes on e.g. writing Curation Tasks can live. We need to distinguish carefully among wishlist and in-progress work on stock DSpace, completed work, and work that we know of which is not stock.
Some of this material is in the Official Documentation: https://wiki.duraspace.org/display/DSDOC6x/DSpace+Development
Some is in the community wiki.