support-core plugin can create incorrect / invalid markdown files as it takes data in plain text and adds it to markdown files.

However the data from jenkisn in plain text may contain markdown characters.

this is the case for the update center - if there is a proxy in use the non proxy hosts can be of the format *.domain.com but this results in that being added verbatim into the update-center.md file, which results in the single * which is not valid.

e.g. non proxy hosts of *.cluster.local|*.example.com will result in the following in the markdown file

 - No Proxy Hosts: 
 * *.cluster.local
 * *.example.com

the markdown in the hostname should be escaped so that it is actually

 - No Proxy Hosts: 
 * \*.cluster.local
 * \*.example.com

https://github.com/jenkinsci/support-core-plugin/blob/1b50a0dfbe22352b117de282bcbd707b8b9bad40/src/main/java/com/cloudbees/jenkins/support/impl/UpdateCenter.java#L77 for one concrete example.