Research how to allow users to easily verify Safe txs on Trezor

[tschubotz]

Problem to solve

#448

Requirements

• [x] Check what info is shown on Ledger and if it can be show/calculated in the Safe interfaces
• [x] Check if https://blog.ledger.com/ethereum-plugins/ is an option
• [ ] Check what info is shown on Trezor and if it can be show/calculated in the Safe interfaces

[sche]

Currently, we implemented tx signing with Ledger Nano X. We display hash on mobile that should appear on the device. I think it does not make sense to research plugin options yet, as it will not improve UX dramatically.

Trezor does not support Bluetooth, so further research could be possible only using Android devices.