build_config.protoascii is an imported file used only for config validation unittesting.
It is imported using copybara:
https://eureka-internal.git.corp.google.com/continuous-tests/+/master/catatester/proto/copy.bara.sky
All updates should instead be made to the original file located at:
https://eureka-internal.git.corp.google.com/builder/masters/+/refs/heads/master/configs/eureka/build_config.protoascii
Changes made under builder/master will take effect shortly after the commit is merged