UOM strange extension situation

I've been granted an assignment extension as I had covid over new years.

The first email I got this morning to confirm this seemed boilerplate, then this afternoon I received an email which was identical to the first except that it included the phrase "Please submit your supporting documentation [here] by [date]", and as I'm a very anxious person (and can't call them now until Monday) I'm not really sure what to do lol

It was my understanding that UOM doesn't ask for evidence for short-term illness so I didn't keep my covid test and as I'm more or less over it now I can't really just...do a new one.

Is this a tech misunderstanding or something? What evidence would they even want? Any advice is helpful 😭