When selected, the link for the Linux installer downloads a .dmg file (same one as is downloaded when selecting macOS -- nrfconnect310.dmg). I'm unable to find another way to download the proper LInux installer.
The issue can be recreated by following the link https://www.nordicsemi.com/Software-and-Tools/Development-Tools/nRF-Connect-for-desktop and selecting Linux from the dropdown. I'm running Ubuntu 18.04 and accessing the page from FireFox.
Thanks!