Example

Page.navigate({"url":"data:text/html,%3Ch1%3EHello%2C%20World!%3C%2Fh1%3E"})
Network.requestWillBeSent({"documentURL":"data:text/html,%!C(MISSING)h1%!E(MISSING)Hello%!C(MISSING)%!W(MISSING)orld!%!C(MISSING)%!F(MISSING)h1%!E(MISSING)","frameId":"ECDF1F217C0F19BA543330D28204F18B","hasUserGesture":false,"initiator":{"type":"other"},"loaderId":"7A23FBAE61A3FDC778C3CD10DFA99435","request":{"headers":{},"initialPriority":"VeryHigh","method":"GET","mixedContentType":"none","referrerPolicy":"no-referrer-when-downgrade","url":"data:text/html,%!C(MISSING)h1%!E(MISSING)Hello%!C(MISSING)%!W(MISSING)orld!%!C(MISSING)%!F(MISSING)h1%!E(MISSING)"},"requestId":"7A23FBAE61A3FDC778C3CD10DFA99435","timestamp":82542.24225,"type":"Document","wallTime":1587519221.375819})
 Network.responseReceived({"frameId":"ECDF1F217C0F19BA543330D28204F18B","loaderId":"7A23FBAE61A3FDC778C3CD10DFA99435","requestId":"7A23FBAE61A3FDC778C3CD10DFA99435","response":{"connectionId":0,"connectionReused":false,"encodedDataLength":-1,"fromDiskCache":false,"fromPrefetchCache":false,"fromServiceWorker":false,"headers":{"Content-Type":"text/html"},"mimeType":"text/html","protocol":"data","remoteIPAddress":"","remotePort":0,"securityState":"secure","status":200,"statusText":"OK","url":"data:text/html,%!C(MISSING)h1%!E(MISSING)Hello%!C(MISSING)%!W(MISSING)orld!%!C(MISSING)%!F(MISSING)h1%!E(MISSING)"},"timestamp":82542.243807,"type":"Document"})
            Page.navigate({"url":"data:text/html,%!C(MISSING)h1%!E(MISSING)Hello%!C(MISSING)%!W(MISSING)orld!%!C(MISSING)%!F(MISSING)h1%!E(MISSING)"}) = {"frameId":"ECDF1F217C0F19BA543330D28204F18B","loaderId":"7A23FBAE61A3FDC778C3CD10DFA99435"}
 Page.frameStartedLoading({"frameId":"ECDF1F217C0F19BA543330D28204F18B"})
      Page.frameNavigated({"frame":{"id":"ECDF1F217C0F19BA543330D28204F18B","loaderId":"7A23FBAE61A3FDC778C3CD10DFA99435","mimeType":"text/html","securityOrigin":"://","url":"data:text/html,%!C(MISSING)h1%!E(MISSING)Hello%!C(MISSING)%!W(MISSING)orld!%!C(MISSING)%!F(MISSING)h1%!E(MISSING)"}})
     Network.dataReceived({"dataLength":22,"encodedDataLength":0,"requestId":"7A23FBAE61A3FDC778C3CD10DFA99435","timestamp":82542.248091})
  Network.loadingFinished({"encodedDataLength":22,"requestId":"7A23FBAE61A3FDC778C3CD10DFA99435","shouldReportCorbBlocking":false,"timestamp":82542.244814})
      Page.loadEventFired({"timestamp":82542.249607})
 Page.frameStoppedLoading({"frameId":"ECDF1F217C0F19BA543330D28204F18B"})
Page.domContentEventFired({"timestamp":82542.252678})

(In reply to Maja Frydrychowicz :maja_zf (UTC-4) (maja@mozilla.com) from bug 1535104 comment #2)

No, keep it as is. We do navigate to data URLs but it's exactly the request traffic that is missing in the implementation.

Maja, given that navigate works as expected it shouldn't block the Page.navigate meta bug, but the meta bugs for the required and still missing events.

Nah, drop it. I was wrong in the last comment. loaderID is returned by Page.navigate.

This got actually done in bug 1632008.