使っていれば見たことあると思うけど、make時に出る
https://i.imgur.com/fHDbTUn.png
https://i.imgur.com/JAvnF7K.png

It is important to note that open source and other publicly available implementations of exFAT do not include a patent license from Microsoft. A license is required in order to implement exFAT and use it in a product or device.
https://www.microsoft.com/en-us/legal/intellectualproperty/mtl/exfat-licensing.aspx