I learned about this from an Indonesian friend, and it’s truly fascinating. The pronunciation is very similar to how China is referred to in Japanese, Korean, and Vietnamese. Btw, we call Indonesia "Yinni".
Today I learnt that the Indonesian name for China is "Tiongkok"! 😂
It's basically Minnan(閩南) or what Singapore calls Hokkien language! 😂
中國 -> Tiong Kok!