What makes you say that? There is literally nothing open source about this chip, nor any secure element, nor any MCU or processor used in any hardware wallet or computing device.
Are you saying this is not true?
This is official github page for this secure element:
https://github.com/Infineon/optiga-trust-mThe MIT License
https://github.com/Infineon/optiga-trust-m/blob/develop/LICENSEIt is not related with Trezor, but github clearly shows that Optiga Trust M secure element have MIT open source license code, and that can be confirmed.
Firmware for Trezor was already open source, so I really don't see any issue here.
This has nothing to do with the chip. This is specifically a software framework to interact with the chip. Like an SDK. Of course it's open source.
Microchip, for example, offers a similar SDK for their secure elements (like the 608b) called "cryptoauthlib" (
https://github.com/MicrochipTech/cryptoauthlib). All code is viewable and they have a basic copyright that doesn't restrict its use (except that it must be used with Microchip products).
This Infineon chip used by Trezor is absolutely no more open than any other competing chip, except that Trezor purchases it without signing an NDA. That's it.