issue2551212 - enable wsgi cache_tracker by default Switch the code so the wsgi cache_tracker optimization is enabled by default. Leave the unoptimized/uncached code path available in case it breaks something. The feature flag can be set to False to disable caching. Updated tests to test the disabled (non-cache) code path. Updated upgrading.txt with info on how to disable caching.

# human timezones
pytz
# indexer
Whoosh
# xapian is also installed
# extra database support
psycopg2
mysqlclient
redis
# encryption
gpg
# java web tokens
PyJWT
# extra HTTP compression methods
Brotli
zstd
# jinja2 template engine
Jinja2