Once you mint CRC, there are three different burning fees applied :
1. Gnosis Fee: 1/12th of the CRC you create. It goes to the team developing Gnosis.
2. Affiliate Group Fee: 1/12th of the CRC you create. It goes to the admins or orgnisation behind the affiliate group you choose (see "What is an Affiliate Group?")
3. Inviter Fee: 1/12th of the CRC you create. It goes to the account whose invite you accepted when creating a Gnosis account. It's limited to a year from whenever you accepted the invite.
All three of these fees are imposed through the use of Gnosis App. They are not part of the core protocol of Circles and you can in principle bypass them by interacting directly with the Circles smart contracts. Circles is an open protocol and there are no secret leaks or fees implemented.
How does the burning fee works?
This article describes the how are allocated the burning fee applied to CRC issuance.