Let’s take this one step at a time:
Well, that’s a shame because the root folder marker (the ending /) is used to signify “give me the default document at this path”. When you neglect to provide it, the browser (or server, if it gets that far) adds it in for you. That is why you’re seeing it supplied for you.
Actually, today, none of what I said is strictly true, but it’s true in practice, or, as you like to call it, de facto.
So this…
… is “more correct”. I say “more correct” because there is more to the restrictions on URL chars than using .*
As to what Katalon is doing to retrieve the URL, it’s probably asking the browser via webdriver. You can do the same by pressing Alt-D, Ctrl-C and then paste into a text file. You will see a site seemingly WITHOUT the trailing slash certainly does contain one.
p.s. I’m 99.99% certain, almost “de jure sure” this isn’t a bug so I’m moving it. If you can come back with a statement as to why it is a bug (possibly ending with QED) I’ll willingly move it back. 