Documentation for generating keybase.txt

The web proof file keybase.txt seems hard to create by hand - is there not a place on the website or a command-line invocation to generate it? I can't find anything in Google or the Keybase docs, or in the command-line help.

Start by checking the Keybase website, existing Keybase documentation, and the command-line help for any way to generate keybase.txt. Document the supported generation path, or clearly explain if the file must still be created by hand.

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