I don't see any problem at https://labs.vmware.com/flings/vsphere-html5-web-client
This is the only public place to download the plugin-seed. If it keeps not working for you send me a private message and I'll give you another link.
BTW, the newer version of plugin-seed should be available next week if you can wait: it supports SDK 6.7 and Angular 6.0.
The link is not working for anyone in our office. Can you please provide alternate way of downloading it?
We need the fling ASAP, so we need to get started with whatever is available right now. We can upgrade it later if that is option. Thank you for you help