Why was this gamer tag a violation?

Where would I find the reason?

Like I said info is too vague

If you didn't submitted an appeal, you can ask that question at the end.

Don't appeal just asking the exact reason, because this can be ignored and the appeal can be denied

If you already appealed, you may need to wait for their response. Usually they add more info

Hi and thanks for reaching Microsoft Xbox gamer's community. My name is Josef.
I'm an Independent Advisor and a Microsoft Xbox user like you.

Hope you're doing great today despite this Branch
Would be great to assist you on this one, but no one here including customer support is capable to assist you with suspensions or enforcement actions.

Because is not possible to access to your account and enforcement details.

The only way to do it is via this site: https://enforcement.xbox.com/ there you can view your enforcement history or start a case review if applicable.

If you want to know how to submit a case review, you can use this link:
https://support.xbox.com/en-US/help/family-onli...

As I said, is only a guess.
We can guess and guess here, but here you can't find the exact reason