Hi Team, It is just another potential optimisation done in Chrome which I came across and wanted to get input whether similar can be done in WebKit or not: Blink Commit - https://chromium.googlesource.com/chromium/blink/+/c0aa7538cb054f429822a3f3cc66efe826122b80 WebKit Source - https://searchfox.org/wubkat/source/Source/WebCore/dom/Document.cpp#6387 ___ In local testing, it compiles but had to use 'committedFirstRealDocumentLoad', which in case of Blink also got changed later in another commit (can't find it). I haven't had any metrics to back up whether it works or not but again it is just for discussion on whether something can be done to get faster page loading or it is just placebo using this idea. Keep making WebKit better. Thanks!
Process prewarming initializes the UA stylesheet among other things, see ProcessWarming::prewarmGlobally()
I don't think this is a priority since we generally load pages into either a prewarmed WebProcess or an existing WebProcess, both of which will have their default stylesheet already parsed at the point of page load.
<rdar://problem/105592243>