This is a 2FA app for iPod.
Inside the apps/totpod/ directory of your iPod Rockbox firmware, create a config file named seeds.cfg with content like this:
UTC=1
otpauth://totp/Wikipedia?secret=NBSWY3DPEB3W64TMMQ&period=30&digits=6&algorithm=SHA1
otpauth://totp/Fly.io?secret=N5WWOIDSMVQWY3DZ&period=20&digits=6&algorithm=SHA1
otpauth://totp/Anthropic?secret=N5XCAYLOEBUXA33EH4&period=30&digits=6&algorithm=SHA1
or you can just enter whatever string is decoded by the QR code when you're setting up 2FA on a website.
https://github.com/kokke/tiny-HMAC-c