Installation in 2020-12 fails silently

[andilem]

When installing the feature group in 2020-12, everything seems to work, but the plugins cannot start.
The Eclipse error log shows:

FrameworkEvent ERROR
org.osgi.framework.BundleException: Could not resolve module: com.reprezen.swagedit [1014]
  Unresolved requirement: Require-Bundle: com.github.eclipsecolortheme; resolution:="optional"
  Unresolved requirement: Require-Bundle: com.reprezen.swagedit.core
    -> Bundle-SymbolicName: com.reprezen.swagedit.core; bundle-version="0.8.0.201909171245"; singleton:="true"
       com.reprezen.swagedit.core [1015]
         Unresolved requirement: Require-Bundle: com.reprezen.swagedit.dependencies; bundle-version="0.8.0"
           -> Bundle-SymbolicName: com.reprezen.swagedit.dependencies; bundle-version="0.8.0.201909171245"; singleton:="true"
              com.reprezen.swagedit.dependencies [1016]
                Unresolved requirement: Require-Bundle: javax.mail; bundle-version="1.4.0"
                  -> Bundle-SymbolicName: javax.mail; bundle-version="1.4.0.v201005080615"
                     javax.mail [1018]
                       Unresolved requirement: Import-Package: javax.activation; version="[1.1.0,1.2.0)"

It seems that the dependencies bundle depends on a very old version of javax.mail, which depends on a very old version of javax.activation, which is not installed automatically.

Manually adding javax.activation 1.1.0 (e.g. from Eclipse 2019-09) to my Eclipse installation resolves the problem.