The Flipswitch API was created by Petrich and A3tweaks. Here's some details via ModMyi.
"Flipswitch is a system that makes it simple to both write switches and tweaks that use switches. Included in it are some of the standard switches you'd expect from a toggle tweak: wifi, bluetooth, hotspot, etc. It does not have any UI—for that you need a tweak that integrates with it, such as Switchicons. Switchicons is an open source example of how as a tweak developer you might integrate with Flipswitch, which is also open source. My intention is to get rid of all the duplicate work that developers have been doing building toggles in their tweaks. As a user, this system will eventually allow using any available switch with any compatible tweak, instead of like now where most toggles are available for SBSettings, but everything else has limited selection."
You can get SwitchIcons from the Big Boss Cydia Repository. The GitHub page for Flipswitch is here.