The first jQuery Migrate pre-release compatible with jQuery 4.0.0-rc.1.

Major changes:

• Core: Remove support for jQuery 3.x (gh-472, gh-555)

• Core: Remove patches for breaking changes in jQuery 3.0.0 or older (gh-472, gh-555)

  The self-closed-tags patch remains, despite being a breaking change in jQuery
  3.5.0, not 4.0.0. There are a few reasons for that:

  1. It's an exception that a breaking change arrived in a non-major version bump.
     Some people may be upgrading from jQuery 3.4.0 or older and it's good to
     make it work for them.
  2. The patch is disabled by default, so the concern of people on newer jQuery
     3.x upgrading to jQuery 4.x with Migrate 4.x getting patches restoring
     behavior from an version older than the pre-upgrade one does not exist.
  3. This was a pretty big break, it may help people update if we still support
     it.

• Core: Don't reimplement deprecated but not removed APIs (gh-472, gh-555)

  This will save space and avoid potential divergence from Core.

  Also, simplify the deferred.pipe patch.

• Core: Use console.info for deprecations without removals (gh-472, gh-555)

  Also:

  1. Group warnings.md by this type.
  2. Rename jQuery.migrateWarnings to jQuery.migrateMessages.
  3. Rename jQuery.migrateDeduplicateWarnings to
     jQuery.migrateDeduplicateMessages.
  4. Adding "info" versions of some internal APIs.

• Core: Provide a package.json exports setup inspired by jQuery Core (gh-524, gh-566)

  The Migrate setup is simpler than Core as it doesn't have the slim or factory
  versions, but the core ideas are similar.

• Core: Don't warn just on access of jQuery.fn.push, etc., but when it's called (gh-571)

• Data: Patch & warn about props from Object.prototype in data objects (gh-561, gh-559)

• Data: Patch $._data as well (gh-569, gh-570)

• Event: Patch jQuery.event.global (gh-574)

• Event: Patch jQuery.event.special's prototype (gh-573, gh-542)

  Allow to use common Object.prototype properties on jQuery.event.special but
  warn as well.

This release introduces only one change:

• Make Migrate properly recognized as a CommonJS module in Node.js (#523, #525)

Note: you may also find jQuery Migrate 3.5.1 on npm. Do not use it, it's a result of a bad release.

Changes:

• Manipulation: Deprecate jQuery.UNSAFE_restoreLegacyHtmlPrefilter (#518)
• Attributes: Fix compatibility with jQuery 4.x (#496, #495)
• Docs: Mark jQuery.fn.load( [ eventData ], handler ) as removed (#482)
• Replace karma and testswarm with jQuery test runner (#503 + followups)