To dump logs you need to run:

brave --no-sandbox --js-flags="--log-all --log-file=/path/to/logs/%t.log" 

There're other flags similar to --log-all that may help you filter logs: https://github.com/v8/v8/blob/a802d5aae5a28f7b762d836429d7c1d4da98537e/src/flags/flag-definitions.h#L2207-L2229

Currently two placeholders available:

• %p - current process ID
• %t - current time in milliseconds

https://github.com/v8/v8/blob/a802d5aae5a28f7b762d836429d7c1d4da98537e/src/logging/log.cc#L2107-L2114

To have a printf-like interface to log any data you can use this snippet:

#include "src/strings/string-stream.h" HeapStringAllocator allocator; StringStream strstream(&allocator); strstream.Add("hello log %d", int_value); strstream.Log(isolate);