For a long time has Bitcoin Core had the ability to run in regtest mode. While the name indicates that this feature is intended for regression testing, it actually serves as a way to create simulated networks – what btcd node runners would know as a simnet.

Even though Bitcoin Core 22 is the first version to support Pay-to-Taproot outputs, its wallet component does not yet initialize with a tr() descriptor by default. While this is expected to change in version 23, there are still reasons to want to import this output descriptor manually.