Files in your data collection can be marked with a read or unread status. This status is only for your own overview, to keep track of all the files you have read or still need to.
When new files are uploaded into the data collection by any other user than yourself, the files get the unread status. This is to show you what items are new and require you to go over them.
Also next to the title of your data collection you can see how many unread items there are, as this is being displayed with a blue pill next to it with a number in it.
You can easily mark items as read if you do not need to review each one individually. To do so, click the three dots to the right of the file and select mark as read or mark as unread.
It also possible to bulk perform this action by selecting multiple files or folders at once.
If you wish to mark everything within a data collection as read or unread, you can click next to the title of the data collection and mark all items as read or unread.