VMware NSX
The VMware NSX branding changed with the release of NSX 4.x by dropping the '-T' of NSX-T and is now referred to simply as VMware NSX.
VMware NSX versions 4.x and up can be found under the 'VMware NSX' product rather than in 'VMware NSX-T Data Center' which ended with version 3.2.x.
To be able to download a file from the support portal, first ensure the "I agree to the Terms and Conditions" checkbox at the top is checked, which may require clicking the link in "Terms and Conditions" beforehand.