What is Gemini custody fee?

Excuse me, could you please elaborate on the Gemini custody fee? I'm interested in understanding what this fee entails and how it is calculated. As a user of the Gemini platform, I want to ensure that I have a clear understanding of all the associated costs. Is the fee a percentage of the assets held in custody, or is it a flat rate? Additionally, are there any additional fees or charges that I should be aware of when utilizing the Gemini custody service? Your insight would be greatly appreciated.