When the trace is enabled, Window Manager and Surface Flinger capture and save current state to a file at each point of interest. frameworks/base/core/proto/android/server/windowmanagertrace.proto and frameworks/native/services/surfaceflinger/layerproto/layerstrace.proto contain the proto definitions for their internal states.
development/tools/winscopeyarn installdevelopment/tools/winscopeyarn run dev