It's not gone, it was changed, previously you had to choose a directory before the export.
Now, after you export you'll get a link to download a zip file and it will be kept in your exports manager.
That's a huge downgrade for me. I was relying on being able to quickly export the html5 project into a folder. I don't want to have to download a zip file, and manually extract it into a folder. I don't know why somebody would want a zip file, but alas, can we at least get the old way back as an option?
I'm integrating my games with my website, and the only way to test that locally is to export it so it can live with my website - the preview just doesn't work for that - so the less effort I have to manually do to export back into a folder the better. I was going to ask for it to remember the last folder it was exported to (or even allow picking the Export Type with the keyboard), but I'll take what it was over what it is now. :/