[PP-1] Remove Internet Explorer 11 polyfills

Postponed on #3263823: Deprecate drupal libraries which are related to Internet Explorer 11 polyfills which are supposed to be removed in D10, these should be deprecated in 9.4.x before they are removed from 10.0.x

Problem/Motivation

Drupal 10 will drop support for Internet Explorer 11: #3155358: [policy, no patch] Drop IE11 support from Drupal 10.0.x. Drupal ship with number of polyfills to accommodate JScripts lack of modern features supported by other JavaScript engines.

Proposed resolution

Based on comments in the core/misc/polyfills files, it seems like all of the polyfills in that folder could be deleted. On top of that, we have couple of polyfills in package.json. From the package.json, we could remove following packages:

• core/css.escape
• core/drupal.array.find
• core/drupal.nodelist.foreach
• core/es6-promise
• core/picturefill
• core/drupal.element.closest
• core/drupal.element.matches
• core/drupal.string.includes
• postcss-calc
• #3272425: Remove Details Aria Polyfill - this is broken out because it needs extensive screen reader testing

Remaining tasks

Complete the issue where these libraries are deprecated in 9.4.x
👉 #3263823: Deprecate drupal libraries which are related to Internet Explorer 11 polyfills which are supposed to be removed in D10

Simply remove these in 10.0.x. We confirmed there is no error if a polyfill is removed even if a module/theme continues to list them as a dependency. The deprecations are available in 9.4 for those who require supporting IE11 etc and have to manually add support that D10 no longer includes.

User interface changes

API changes

Data model changes

Release notes snippet