The plugin code seems to be infected by some kind of advertisement malware, which displays advertisement text in the Jenkins configuration interface.

The code is clearly visible also in the github repo:
https://github.com/jenkinsci/analysis-core-plugin/blob/9f8f492d2931981f91a06a8eb0123fd7d3cd1a58/src/main/resources/index.jelly

Maybe it will start spreading to other plugins and after a while the Jenkins backend will look like a typical WordPress admin backend, so this should be removed quickly before this disease can spread across the whole ecosystem.