This is the max message size that DevTools can emit over the DevTools protocol: https://cs.chromium.org/chromium/src/content/browser/devtools/devtools_http_handler.cc?type=cs&q=kSendBufferSizeForDevTools&sq=package:chromium&g=0&l=83 Test is failing on firefox since Firefox crashes when allocating 100Mb string. Fix #4543