playwright/browser_patches/firefox/cheatsheet.md

Debugging

Stack trace

It mozglue/misc/StackWalk.cpp add

#define MOZ_DEMANGLE_SYMBOLS 1

In native code use

nsTraceRefcnt::WalkTheStack(stderr);

If the stack trace is still mangled cat it to tools/rb/fix_linux_stack.py

Logging

MOZ_LOG=nsHttp:5

Module name is a string passed to the mozilla::LazyLogModule of the corresponding component, e.g.:

LazyLogModule gHttpLog("nsHttp");