Django Debug Toolbar > Panels > Default built-in panels, Third-party panels, API for third-party panels: https://django-debug-toolbar.readthedocs.io/en/latest/panels...

Firelogger.py//middleware.py: https://github.com/binaryage/firelogger.py/blob/master/firep...

Distributed tracing w/ OpenTelemetry, Jaeger; Metrics with ~JMX

W3C Trace Context v1: https://www.w3.org/TR/trace-context-1/#overview