I am presently using Gnome 3.38.4 but when I opened Zorin this morning I get this message ..... apparently for a download .... Gnome Platform 42 ..... if this is an update is it safe ..... I generally like to wait a bit to insure ll the bugs are worked out ....
This is in regards to Flatpak packages, only. It will not damage your system if you accept the download.
It only provides dependencies needed for certain flatpak applications.
If you are not using Flatpak apps, you can ignore it.
If you are not using Flatpak at all and do not intend to, you can rid yourself of the message with
sudo apt remove --purge flatpak