Hit the 'contact us' link, then browse the sub-menus until you find something close enough in context to submit your inquiry so you can start a dialog w/support.
I don't believe there is a shortcut, otherwise.
Why Apple does not respond here, how to download linux distribution of Transporter
I'm also trying to download Transporter for Apps for Linux, but can't find it anywhere.
I asked from Apple support, but got instructions to ask from the forums.
There are links for Transporter for Music, Books, Videos and TV in Transporter User Guide 2.0 https://help.apple.com/itc/transporteruserguide/en.lproj/static.html, but no link for Transporter for Apps. See "Install Transporter on Linux" section.