T96326 details the implementation of the MobileWebSearch event logging. Soon after it got derployed it very-nearly-almost melted the EventLogging infrastructure. It was promptly disabled.
- MobileWebSearch event logging is enabled – at the very least, 209296 is reverted)
- Is marking the SchemaMobileWebSearch class as sampled enough? MobileWebSearch events share a couple of identifiers so we track a user's search experience from opening the search UI to clicking on a result. The existing sampling implementation is per Schema#log call. This might have to be configured as an experiment.