What is the fine-grained topic of the following text: This whole package by now is not wholly developed by CyanogenMod developers alone, but is a collaborative effort between them and independent developers on sites like XDA-Developers.CyanogenMod right now, is based on Android 2.3 Gingerbread and referred to as CyanogenMod 7. Only return the topic.
Development and collaborative effort of CyanogenMod 7 based on Android 2.3 Gingerbread