Current situation is that a new description is appended to the previous one. It can work for a simple freestyle job quite well.

A different situation is for matrix job where (if allowed) via MatrixAggregator we collect all descriptions from matrix items together.

A common use-case is:

• job's type is a Matrix job
• job has a parameter (at least one)
• the parameter is a build identification which is tested
• description of the run contains that parameter (its value)
• we want to distribute that info to the matrix parent build as well

Especially the last item means, we want there only one description and not concatenation of all descriptions (the same description repeated how many items (configs) we have in the matrix). On the other hand also simple freestyle project can benefit from this feature as well, so I'm not going to limit it to the Matrix project only.

If we allow an user to configure appending a description by this way, we can cover more use-cases with the meaningful result.