Logging sanitized user-agents allows us to diagnose browser-specific performance and usability issues. UAs have already been logged as part of http://meta.wikimedia.org/wiki/Schema:NavigationTiming and we added them to the instrumentation requirements for http://meta.wikimedia.org/wiki/Schema:Edit.
This proposal is to make UA a default field logged by EventLogging for all client-side events.
Version: unspecified
Severity: normal
See Also:
T58575: Browser and platform stats for logged-in vs. anon users for security and product support decisions