Katana Librarian is a free Android app developed by Apps For Amps that allows you to connect your phone or tablet to your BOSS Katana amplifier via USB or a Bluetooth adapter (sold separately). The app unlocks your amp's full potential by allowing you to download patches from your amplifier and modify the patch parameters, including support for all effect types. You can also access undocumented Katana features like hidden amps and multiple simultaneous effects, and organize your patches into groups, tag your favorite patches, or create a set list for a live performance. The app also features a hotkey function that, when used in combination with a Bluetooth MIDI or HID foot switch, enables hands-free patch and effect switching. Additionally, you can import and export MkI and MkII .TSL files, rename and delete patches, and write patches to the amplifier's channels. Please note that the app is not affiliated with or endorsed by Roland Corporation in any way. BOSS is a registered trademark of Roland Corporation.