Can someone please explain this to me or point me to somewhere this will be explained

Themed pets are specialized Sylesties that can only be found in the wild or obtained through other means at certain times of the year (usually during festivals and then limited to festival zones). A themed pet will have a certain specific colour palette, but this specificity is not usually limited to traits. There are a few themed pet examples that are both limited to colour palette and trait. One such example is the Windchaser luffox.

A Purebred themed is typically offspring where both the father, mother and any other relatives are of the same theme. You can usually tell if a pet is themed because it should have a purple name underneath its species, gender and children information. For example:

Species: Luffox
Breed: Sylesti
Gender: Female
Children: 1
This is an Exclusive Sylesti
Ruby Orchid Luffox

or

Species: Aurleon
Breed: Sylesti
Gender: Male
Children: 1
This is a Tamed Sylesti
Autumn Wind Aurleon

There are also exclusive themed and regular themed...and these differ depending on their modes of being obtained. An exclusive sylesti is usually obtained by doing a specific task within said festival. They can be obtained through official contests, games or through events like gardening or baking.

Regular themed are usually found through exploration during festival times.

PB themed offspring aren't named. You can tell that they are legitimately purebred by tracing their lineage back to the original parents and seeing if there is a golden star within the window of the original themed parents.

Finally, there are some themed pets that are not tagged. These themes were released by the admins before they started tagging them. These themed can be quite difficult to find.

Here is a thread you can visit for more information.

https://www.sylestia.com/forums/?thread=15459

thank you so so much :)