You can just hit F12 on that page to open the browser's dev tools and monitor the calls being made under the Network tab. Microsoft has been working hard to make sure almost everything in the Entra ID portal is backed by running the corresponding Graph API requests, so if you ever want to see what the exact method/call is, F12 is the easiest way.
As for the export, I'm afraid it's hard-coded. You can however easily mimic the behavior via the Graph SDK for PowerShell and the Get-MgUser cmdlet. If you need a quick check whether the user is licensed, you simply need to check the whether the assignedLicenses property has a non-null value. Here's a quick example:
Get-MgUser -All -Property Id,DisplayName,JobTitle,assignedLicenses | select Id,DisplayName,JobTitle,@{n="IsLicensed";e={if ($_.assignedLicenses) {$true} else {$false}}}
Make sure to add any remaining properties as you see fit. The downside of having to do this via the module is the crappy syntax it uses, as you have to add each property you want displayed twice (once for the -Property parameter and once for the select statement).