For example, https://gerrit.wikimedia.org/r/#/c/181386/ :
07:33:36 The module 'schema.UniversalLanguageSelector' required by 'ext.uls.eventlogger' must exist
07:33:36 Failed asserting that an array contains 'schema.UniversalLanguageSelector'.
It's either an issue in ULS or in Jenkins, and I'm inclined to think that it's the latter. AFAIK, ULS registers its schema correctly using the EventLoggingRegisterSchemas hook, and not by registering a module explicitly. If I am right, then the job must be made non-voting until it's fixed to support this way of registering schemas.