Phone verification without SMS

I updated to the latest Keybase GUI and was prompted to enter a phone number as a way of people looking me up. After entering my number, I discovered that entering a code sent via SMS is required to verify the number. I have SMS disabled on my phone line for security purposes. Is there an alternative way of doing phone number verification?

The issue describes phone-number verification in the Keybase GUI but names no implementation files, tests, or entry points. Start by locating the phone verification flow and its product and security requirements; done would require an approved alternative to SMS that preserves verification guarantees and is covered by appropriate tests.

Written by the indexing model from the issue text.