Hi guys, the action on this issue is long overdue. I've checked the usage on https://www.chromestatus.com/metrics/feature/timeline/popularity/1668. Currently it is around 12% if I understand it correctly. What is the recommended threshold here to make the decision?

The current usage is 0.16% or so, but there's no hard threshold for when removal is considered. Hard breakage of 0.16% of page views would be far too much, so the question is what that 0.16% means.

If this is an API that's possible to grep for in httparchive, then it might be possible to get a better idea that way. The final section of https://docs.google.com/document/d/1LSuLWJDP02rlC9bOlidL6DzBV5kSkV5bW5Pled8HGC8/edit?usp=sharing has some guidance about this, and links to other resources that might be useful.

Here's what I think we should do here:

0. Immediately deprecate and remove extending SVG elements in V0, because use
   counters tell us nobody does that in practice.
   https://www.chromestatus.com/metrics/feature/timeline/popularity/1875

1. Make createElement('div', {is: 'my-div'}) create V0 and V1 custom elements;
   make createElement('div', 'my-div') not create V1 custom elements. (I've
   equivocated about this, but I think this is the right thing to do.)

2. Ship customized built-in elements ( Issue 652579 ).

3. Do developer outreach to switch from v0 type extensions to v1 customized
   built-ins, and v0 custom tags to v1 autonomous custom elements.
   https://www.chromestatus.com/metrics/feature/timeline/popularity/1878
   https://www.chromestatus.com/metrics/feature/timeline/popularity/1877

4. Remove "embedder custom elements" to some other solution.
   https://www.chromestatus.com/metrics/feature/timeline/popularity/1876

5. Deprecate, then remove v0 APIs.

(Needless to say, the string, string createElement override can go during step 5 if not before.)

Removing owner and marking as untriaged since there's been no activity for a while. a.obzhirov, if you intended to work on this, please assign it to yourself again, and sorry for the disturbance.

Making this available again.

 Issue 701550  has been merged into this issue.