Jitterbug is an iOS app that lets you to wirelessly connect to another iOS device (neither are jailbroken) and then launch an app on the connected iOS device with JIT enabled. This can be used with UTM or DolphiniOS or other supported apps for faster emulation speed.
On jailbroken devices, TrollStore compatible devices, or any device with a paid developer account, Jitterbug can create a VPN tunnel to run apps on the local device without needing a second device.
Jitterbug Lite is the same app without any of the VPN features which require special entitlements only available to paid Apple Developer accounts.
Note: Only Jitterbug Lite will work with AltStore!