Steps to reproduce:
1. Browse to https://docs.opencast.org/develop/developer/development-environment/#attaching-a-remote-debugger-to-karaf
2. Be curious about more details and follow the link
titled "this site"
3. Be redirected to https://karaf.apache.org/manual/latest/developers-guide/debugging.html
The link is dead and also outdated, since Opencast uses Karaf 4, not 2.
Find a site with more information about remote debugging with Karaf,
Workaround (if any):
Google for the information and find https://karaf.apache.org/manual/latest/#_debugging. Unfortunately there does not seem to be a link dedicated to version 4, which would "survive" the release of a new Karaf version in the sense that it would still point to the correct documentation for the version we use.