The last version of this library that's been published to c.g.c. is v1.43.2 (https://cloud.google.com/java/docs/reference/google-http-client/latest/overview.html). I double-checked the Cloud RAD bucket, and confirmed that v1.43.2 is the latest tarball that's been uploaded to the bucket.

This means there's something wrong with the release process for this library such that the tarball doesn't get generated/uploaded to the Cloud RAD bucket. I suspect the migration of the release jobs to Kokoro from Github likely broke this.