I’m the author reporting this bug. Simple to fix but may take few days as I need time to test.

The bug – when de-activating the migrate plugin, it unregisters the handle.

That is the wrong behavior.

What SHOULD happen –

When migrate is active, scripts that require “jquery-core” should also get “jquery-migrate” because scripts written for jquery-core in WordPress may actually need the migrate if jQuery 3.5.1 is being used.

When migrate is disabled, scripts that ask for “jquery-core” then only get 3.5.1 but scripts that ask for “jquery” or “jquery-migrate” should still get it, so it should not be de-registered.

Hopefully I will have time to fix today and test in next few days and push the fix.