This is used when cloning a node to attach the binding before it's added to the DOM: https://searchfox.org/mozilla-central/rev/efce4ceddfbe5fe4e2d74f1aed93894bada9b273/dom/base/nsNodeUtils.cpp#725-742. As far as I can tell, we don't rely on this in m-c. I did a try push with that code removed and the main failure I see is a XBL-specific test (dom/xbl/test/test_bug398492.xul): https://treeherder.mozilla.org/#/jobs?repo=try&revision=7637b0ecba8cdffccf243874e80e6af1f1b9c39c.

Jorg, last I checked there was c-c code that relied on this hackery. Do you mind doing a c-c equivalent of that try push and seeing whether there is still fallout?

I'm not sure what this is all about, where we would rely on this and what to look for, but here you go: https://treeherder.mozilla.org/#/jobs?repo=try-comm-central&revision=b29618c769e7142e6b71a3a72e74c5427688674c One Xpcshell test failure currently expected due to bug 1443769.

> I'm not sure what this is all about This is about removing the mechanism that force-applies XBL bindings to elements that are not in the document which happen to be clones of other elements. > where we would rely on this Last I checked, the mailcompose header bits relied on it... Thank you for the try push!

Looks like mozmill/session-store/test-session-store.js | test-session-store.js::test_message_pane_height_persistence failed.

Please ignore comment #4, this failure is new on the tree, see bug 1444045.

Great! Let's move forward here. Do the TB folks have a plan for when XBL/XUL start rapidly shrinking/changing and eventually go away? That's on the roadmap for 2018...

> Do the TB folks have a plan for when XBL/XUL start rapidly shrinking/changing and eventually go away? Afaict, no.

Comment on attachment 8958174 [details] Bug 1443948 - Remove NODE_FORCE_XBL_BINDINGS; https://reviewboard.mozilla.org/r/227120/#review233326 r=me

Pushed by bgrinstead@mozilla.com: https://hg.mozilla.org/integration/autoland/rev/dbf853820066 Remove NODE_FORCE_XBL_BINDINGS;r=bz