Long story short:

┌─ ~/work/docker-glibc 1m20s
└─❯  docker run -ti --rm archlinux:base-20210214.0.15477 getconf -a | grep "GNU_LIBC_VERSION\|LEVEL1_ICACHE_LINESIZE"
GNU_LIBC_VERSION                   glibc 2.33
LEVEL1_ICACHE_LINESIZE
┌─ ~/work/docker-glibc 1m8s
└─❯  docker run -ti --rm archlinux:base-20210131.0.14634 getconf -a | grep "GNU_LIBC_VERSION\|LEVEL1_ICACHE_LINESIZE"
GNU_LIBC_VERSION                   glibc 2.32
LEVEL1_ICACHE_LINESIZE             64
```