I don't know what this is used for but is there any action we should be taking to treat this prior to March 2019? Will it affect anything at all? This appears to be used in out of the box code out of our control.
It looks like that specific function is not widely used in the Pega platform (it is mostly used by some 3rd party libraries that we no longer use). The only thing that is of concern is it'sbeing used by pzpega_ui_jstree which is a 3rd party library we use for the Live UI feature.
We can fix this in the latest version of Pega and also, depending on the severity of usage, we sometimes create pro-active hotfixes to replace the function that is going to be deprecated by the browser.
For now this looks like nothing to be concerned about but we will try to fix this in our current version of Pega and in our patch releases for Pega 8.1 if feasible.
A little more "back story" to follow on Meghan's comment. This is Chrome's note that it will be deprecating the "old" Custom Elements 0 standard that has been replaced by the Custom Elements 1 standard. The evolution from Custom Elements 0 to Custom Elements 1 has been on-going for a while. (Chrome included Custom Elements 0 back in Chrome 33.)
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