The data frame and chat UI work has added assets in www/shared/py-shiny, but the HTML dependency-updating script in scripts/htmlDependencies.R has always deleted and recreated this directory.
We could carve out an exception for www/shared/py-shiny or we could move the directory to www/shared. I'm in favor of the second option because we rely on deleting and recreating www/shared to also delete unneeded files during the upgrade.
cc @schloerke @cpsievert