the plugin contains 120 libraries in `WEB-INF/lib`

Many (most of) these should actually come from Jenkins core or plugins and not be bundled

e.g. bouncycastle libraries should come from a dependency on the bouncycastle-api library and not be bundled.  simillary for eddsa

spring-core and spring-context are examples of libraries which should not be bundled as they are provided by virtue of running inside Jenkins (the container contains these).

There are numerous other examples of this also.