As for telling whether it's a production or test system, you might want to consider $SYSTEM.Version.SystemMode(). Calling that function with no argument will return the current system mode, which can be DEVELOPMENT, LIVE, TEST, or FAILOVER. It's usually set in the System Management Portal, but you can also call that function passing any of those strings are an argument to set it programmatically.

Assuming that's a typo and the last one is supposed to be Class BZ.Test3, this is all correct and as expected. Since it extends Test2, Test3's onloadHandler function is identical to Test2's onloadHandler, which runs its superclass's onloadHandler and prints test2. Since its superclass is Test2, it's superclass's onloadHandler is also running its onloadHandler, then printing test2. Since Test2's superclass is Test1, Test2 is running its superclass's onloadHandler, printing test1.

Remember, removing the onloadHandler method from Test3 doesn't mean that it doesn't have an onloadHandler; it just means its onloadHandler is the same as the one in its superclass, Test2.

Have you checked the timeout on the web application?

See this FAQ and look for the question "I closed my CSP session, but Caché still reports that I am using a license. Why?" I don't know much about your specific application, but that may be what you're running into. CSP sessions have a grace period that, frankly, doesn't make much sense at all. That FAQ explains how long the CSP session grace period lasts, and the question after that is about how to set the timeout for your web applications. Doing so appropriately will minimize the grace period.

FYI, the reason this is so difficult is because an XLSX file is actually a ZIP archive with a bunch of XML files in it. You'd actually have to save the file as a .ZIP, extract it, navigate to the XML files for the worksheets (on the current version, that's inside the archive in \xl\worksheets, but that's changed between versions if I remember correctly) then parse the data out of the XML file and write it to your CSV file. That's why there are all these third-party tools people are recommending to handle this issue.

Phil, I'm not sure about VS Code, but you can do this in studio by creating a new CSP page with the following contents:

<csp:StudioSimpleTemplate name="CustomCommentHead" type="CLS" mode="new">
/// Organization:
/// Version 1.0
/// Author/Co-author:
/// Project: 
/// Date: 
/// Description: 
/// Change Log:
/// Notes:

Then save and compile that file. It doesn't matter where. Then when you click File, New, Custom, you'll see your CustomCommentHead template. If you choose it, you'll get a .cls file with those lines already inserted.