Where I can download the x86_64-openwrt-linux-musl-gcc 5.2.0 version

dear guys,

Do you know where I can download the 5.2.0 version of x86_64-openwrt-linux-musl-gcc too chain?
I download the sdk docker image, the latest version is 8.4.0.
I do not know which gcc version was included in the sdk docker image.
Can you give me some hints? Thank you!