function-orchestrator code can be found at https://gerrit.wikimedia.org/g/mediawiki/services/function-orchestrator
src/implementation.js (line 56, or search for T296682 within the file)
Find and fix any cases within the code base where a builtin implementation's identity is a ZReference (Z9) instead of a ZString (Z6).
An Implementation (Z14) is builtin if Z14K4 is populated. Z14K4 should always be a ZString (Z6).