sh(wpkh(
I initially read that as do a shell script with a custom wpkh executable but now not sure. Is it shell script or is this something in the wallet descriptor format I should be learning about?
Wallet descriptors are just auxiliary information to help other programs identify the script type of an address, sort of like how you can have a "1", or "3", or "bc1" address for each private key but you want to identify which address type, except each of these maps to a script type, which is what wallet descriptors try to identify.
For this wallet descriptor, the
wpkh stands for P2WPKH, and the
sh stands for P2SH. The
wpkh is evaluated before the
sh, hence it's read as P2SH-P2WPKH.