@eicke Search this community website for:
Dial connector

And see the M5Stack Dial document page here:
https://docs.m5stack.com/en/core/M5Dial

0_1711040448858_1709937244466-screenshot-2024-03-08-at-5.33.53-pm.png

https://m5stack.oss-cn-shenzhen.aliyuncs.com/resource/docs/products/core/M5Dial/DB2EK-2.54-2P-GN-S 2.54mm 2Pin Green.pdf

Also I just realized that the actual 2 pin part number is in the URL of the datasheet!
DB2EK-2.54-2P-GN-S
\o/