Weird user group numbers

I recently, less then two days, installed Fedora MATE 30 in my laptop. I noticed some weird user groups in the terminal and I investigated. Here are the results:

$ cat /etc/group | grep -E "1000|1001|1002"

user1 is myself, the admin user that was created during the installation. However up to now, on my previous linux distros, my user’s group ID has always been 1000 and the second’s user has always been 1001. I this that has also been the case when I used Fedora (ie GNOME DE). Any idea why I am seeing different user group numbers now?