Some of the io.prometheus packages do not have information in the Maven Central Mirror bucket: https://console.cloud.google.com/storage/browser/maven-central;tab=objects?inv=1&invt=Ab3iqA&prefix=&forceOnObjectsSortingFiltering=false
Some few examples are:
Among others.
A common theme is that they all stop at version 1.3.1 despite the fact that there are newer versions of these packages.
All these are currently at version 1.3.10.
Could this be an issue with the synchronization of io.prometheus packages specifically with the bucket?