jQuery 3.0 disables the guessed dataType: 'script' for cross-domain URLs. See https://github.com/jquery/jquery/commit/b078a62013782c7424a4a61a240c23c4c0b42614 and: https://jquery.com/upgrade-guide/3.0/#breaking-change-cross-domain-script-requests-must-be-declared
jQuery 3.0 disables the guessed dataType: 'script' for cross-domain URLs. See jquery/jquery@b078a62 and:
https://jquery.com/upgrade-guide/3.0/#breaking-change-cross-domain-script-requests-must-be-declared