What is this feature about? (1 sentence)

This allows users to configure custom endpoints in the app in order to not be dependent on Gnosis infrastructure.

Why is it needed? What is the value? For whom do we build it?

Users might want to use their own node/ RPC endpoint to interact with the Gnosis Safe. The old Gnosis Multisig also allowed to use a custom node.
This helps enabling the Safe as a truly self-custodial wallet without the need for Gnosis services to be run.

This is a feature for a very specific niche of users, so it can be hidden away in an advanced section of the settings. This is also optional for the web interface, as the users of this feature would probably always opt for the Desktop App anyways. So if it would mean additional complexity to work with the web app as well, it can be Desktop-exclusive.
In the settings, the user sees the following settings:
- Tx service endpoint
- rpc endpoint
User can edit these settings.
User can easily reset them to the default.