Playing with the API sandbox, the networks listed don't always contain all the available testnet networks. Specifically, I found the following pages are missing quite a few networks that are listed in the /lib/chains.json file.
/debug/beta/addressBook/create/debug/beta/addressBook/create/fetch
I'm building on Stellar, so I tested locally including the Stellar/XLM chain on those pages, and things seem like they worked fine. There may be more pages that are missing some networks.
Playing with the API sandbox, the networks listed don't always contain all the available testnet networks. Specifically, I found the following pages are missing quite a few networks that are listed in the
/lib/chains.jsonfile./debug/beta/addressBook/create/debug/beta/addressBook/create/fetchI'm building on Stellar, so I tested locally including the Stellar/XLM chain on those pages, and things seem like they worked fine. There may be more pages that are missing some networks.