With bookworm, things have significantly changed; it seems webkit2gtk is now pretty much broken on non-local displays, but then the crashes are somewhat milder.
I believe the easiest webkit client to investigate the problem in is surf, where the raw symptom is: $ ssh -X <somehost> surf http://www.debian.org libEGL warning: DRI2: failed to authenticate (WebKitWebProcess:498): Gdk-WARNING **: 13:11:26.540: The program 'WebKitWebProcess' received an X Window System error. This probably reflects a bug in the program. The error was 'BadRequest (invalid request code or no such operation)'. (Details: serial 173 error_code 1 request_code 154 (unknown) minor_code 1) (Note to programmers: [...]) web process terminated: crashed Regrettably, this time I can't get the WebKitWebProcess to dump core -- is there a simple knob to make it do that on a X error? As usual, the things die faster than you could attach to them. On the plus side, it seems the crashes are now a fairly solid feature that I'm seeing independent of particular screens on particular graphics cards. Oh, and, Good News: with WEBKIT_DISABLE_COMPOSITING_MODE=1 things are just fine: $ ssh -X <somehost> env WEBKIT_DISABLE_COMPOSITING_MODE=1 surf http://www.debian.org works in every combination I've tried. If you say "live with disabling compositing mode" I suppose I could live with closing this bug.
