What is Roon downloading in the background?

I am running Roon core on an iMac in my office and occasionally I notice Roon downloading megabytes of data while not playing but idle in the background.
Any idea what it is doing?

It will be updating metadata for items in your library. This could include updated artist and album images, album reviews etc. The information will end up in your local Roon database.

Many thanks for the replies.
Put’s my mind at ease.