I'd just like to mention that turning an adjective (e.g. "roundabout") into an adverb by adding -ly is not particularly unusual. That is the standard way to form an adverb from an adjective. And it would also come as no surprise to me if people occasionally misspelled the adjective "roundabout" by writing it as two separate words.
Could you give us the context? Where did you see or hear it? It doesn't make any sense to me at all, and I'm not convinced it's short for "roundaboutly" (which is not a very common word itself -- usually we would say "in a roundabout way"). I'm wondering if it's a typo for "absolutely" or "abruptly" or something else.
Hi! Thank y'all for answers. Here is the original. It's a sort of technical instruction
"In the Due date field, enter a day, month, and year for the task group to be completed. This field is for your information aboutly. The program does not perform any actions based on this date." I doubt that it's a typo. Firstl