Gobbledygook error from 'devel clean'

[tic20@…]

The following bug report has been submitted:
Platform:        Windows-10-10.0.17134
ChimeraX Version: 0.91 (2019-07-27)
Description
New warning appears when running "devel clean" on Clipper.

Log:
UCSF ChimeraX version: 0.91 (2019-07-27)  
© 2016-2019 Regents of the University of California. All rights reserved.  
How to cite UCSF ChimeraX  

> cd "C:\\\Users\\\tic20/my-gits/chimerax-clipper"

Current working directory is: C:\Users\tic20\my-gits\chimerax-clipper  

> devel clean .

C:\Program Files\ChimeraX-daily\ChimeraX\bin\lib\site-
packages\packaging\requirements.py:57: UserWarning:
warn_ungrouped_named_tokens_in_collection: setting results name 'specifier' on
And expression collides with '_original_end' on contained expression  
VERSION_SPEC = originalTextFor(_VERSION_SPEC)("specifier")  
C:\Program Files\ChimeraX-daily\ChimeraX\bin\lib\site-
packages\packaging\requirements.py:60: UserWarning:
warn_ungrouped_named_tokens_in_collection: setting results name 'marker' on
And expression collides with '_original_end' on contained expression  
MARKER_EXPR = originalTextFor(MARKER_EXPR())("marker")  
  




OpenGL version: 3.3.0 NVIDIA 399.24
OpenGL renderer: GeForce GTX 1070/PCIe/SSE2
OpenGL vendor: NVIDIA Corporation

[tic20@…]

Also got the same warning messages for ISOLDE, so it’s probably not bundle-specific. Bundles still build OK.