Shelving v2 and v3 both available, selectable by env. var.:
Merged in http://svn.apache.org/r1875037 and -038.Changed the default to both versions disabled, in http://svn.apache.org/r1875039 and -040.
I wrote up a short review of the shelving implementations the other day: https://blog.foad.me.uk/2020/03/02/svn-shelving-development-review/
Copied to SVN wiki: https://cwiki.apache.org/confluence/x/MxbcC - Julian
