I recently had trouble checking out the codeblocks-python external.
Getting error svn: E175003 https://github.com/... does not support the HTTP/DAV protocol
It seems that there are some problems with github and the new subversion-1.11.0 (see https://bugs.freebsd.org/bugzilla/show_bug.cgi?id=232945 (https://bugs.freebsd.org/bugzilla/show_bug.cgi?id=232945)). If you can, reverting to subversion-1.10.3 works around the problem.
Ross