requires manually specifying layout if only part of the repository is accessible

Observe:

E:\home\zotero>bzr info https://www.zotero.org/svn/extension
HTTPS www.zotero.org username:
<https://www.zotero.org:443> Zotero Dev password:
HTTPS www.zotero.org username:
<https://www.zotero.org:443> Zotero Dev password:
bzr: ERROR: subvertpy.SubversionException: ("PROPFIND of '/svn': authorization failed: Could not authenticate to server: rejected Basic challenge (https://www.zotero.org)", 170001)

Traceback (most recent call last):
  File "bzrlib\commands.pyo", line 912, in exception_to_return_code
  File "bzrlib\commands.pyo", line 1112, in run_bzr
  File "bzrlib\commands.pyo", line 690, in run_argv_aliases
  File "bzrlib\commands.pyo", line 705, in run
  File "bzrlib\cleanup.pyo", line 135, in run_simple
  File "bzrlib\cleanup.pyo", line 165, in _do_with_cleanups
  File "bzrlib\commands.pyo", line 1127, in ignore_pipe
  File "bzrlib\builtins.pyo", line 1502, in run
  File "bzrlib\info.pyo", line 328, in show_bzrdir_info
  File "E:/Tools/Bazaar/plugins\svn\remote.py", line 253, in open_branch
  File "E:/Tools/Bazaar/plugins\svn\remote.py", line 265, in _open_branch
  File "E:/Tools/Bazaar/plugins\svn\branch.py", line 211, in __init__
  File "E:/Tools/Bazaar/plugins\svn\repository.py", line 642, in get_layout
  File "E:/Tools/Bazaar/plugins\svn\repository.py", line 664, in get_layout_source
  File "E:/Tools/Bazaar/plugins\svn\repository.py", line 684, in _find_guessed_layout
  File "E:/Tools/Bazaar/plugins\svn\layout\guess.py", line 143, in repository_guess_layout
  File "E:/Tools/Bazaar/plugins\svn\logwalker.py", line 254, in iter_changes
  File "E:/Tools/Bazaar/plugins\svn\logwalker.py", line 330, in _fetch_revisions
  File "E:/Tools/Bazaar/plugins\svn\transport.py", line 589, in get_log
SubversionException: ("PROPFIND of '/svn': authorization failed: Could not authenticate to server: rejected Basic challenge (https://www.zotero.org)", 170001)

bzr 2.2.1 on python 2.6.4 (Windows-XP-5.1.2600-SP3)
arguments: ['bzr', 'info', 'https://www.zotero.org/svn/extension']
encoding: 'cp1252', fsenc: 'mbcs', lang: None
plugins:
  bzrtools E:\Tools\Bazaar\plugins\bzrtools [2.2.0]
  colo E:\Tools\Bazaar\plugins\colo [0.1.0]
  explorer E:\Tools\Bazaar\plugins\explorer [1.1.0]
  fastimport E:\Tools\Bazaar\plugins\fastimport [0.9.0dev]
  launchpad E:\Tools\Bazaar\plugins\launchpad [2.2.1]
  loom E:\Tools\Bazaar\plugins\loom [2.2.1dev]
  netrc_credential_store E:\Tools\Bazaar\plugins\netrc_credential_store [2.2.1]
  news_merge E:\Tools\Bazaar\plugins\news_merge [2.2.1]
  pipeline E:\Tools\Bazaar\plugins\pipeline [unknown]
  qbzr E:\Tools\Bazaar\plugins\qbzr [0.19.2]
  rewrite E:\Tools\Bazaar\plugins\rewrite [0.6.1]
  svn E:\Tools\Bazaar\plugins\svn [1.0.4]
  upload E:\Tools\Bazaar\plugins\upload [1.0.0dev]
  xmloutput E:\Tools\Bazaar\plugins\xmloutput [0.8.6]

*** Bazaar has encountered an internal error. This probably indicates a
    bug in Bazaar. You can help us fix it by filing a bug report at
        https://bugs.launchpad.net/bzr/+filebug
    including this traceback and a description of the problem.

It seems that that path really *is* inaccessible, but that should that really be an issue if the repository is split into "projects", each with their own branch structure, only one of which (extensions) I am asking to import?