title: Problem with multibranch pipeline jobs with branches that have a slash in their name
body: <p>There has been many stackoverflow questions about various issues related to multibranch pipeline with slash in their branch name.  I have even created a Jenkins <a href="https://issues.jenkins-ci.org/browse/JENKINS-57324" rel="noreferrer">JIRA</a> for my specific situation (latest Jenkins + plugins and config file provider plugin).  However  I would like to get some clarification.  I tried looking at the source code but I got lost because the pipeline plugin used to be called the workflow plugin and now the source code project is called workflow-aggregator (I think) but when I look at this plugin I cannot understand how it relates/include the other plugins in the list of plugins.  Here are my observations(I am on Windows if that matters):</p>
  
  <ol>
  <li>It used to be that Jenkins would use the three characters %2F in folder names in place of / in branches.</li>
  <li>Then this was changed to _ instead of %2F</li>
  <li>Now it is back to %2F (with all latest plugins)</li>
  </ol>
  
  <p>So here are my questions:</p>
  
  <ol>
  <li>Is there somewhere documented why %2F was re-instated?</li>
  <li>Could someone point me to which plugin and what version last used _ instead of %2F as this is causing me grief and I would like to work around this?</li>
  <li>Is there some code I could put to configure this behaviour with the existing latest plugins?  I saw this <a href="https://support.cloudbees.com/hc/en-us/articles/226122247-How-to-Customize-Checkout-for-Pipeline-Multibranch-" rel="noreferrer">post</a> but it does not provide me with an example for declarative pipelines and with SVN as the SCM.  The issue with declarative pipelines is that the code in this post requires you to disable the declarative SCM checkout step (using the skipDefaultCheckout() option) and I do not know how to configure the branch folder path name.  I do not want the remote URL to be specified in the Jenkins file but rather in the Jenkins job configuration.</li>
  </ol>
  
  <p>Any help is truly appreciated</p>