There is an extraenous asterisk in the constructor description for class 'threading.Thread' in section 17.1.2. "Thread Objects" of the 'threading' module in the Python Standard Library documenation. (patch attached)
Thanks for taking the time to make a report, but that is not a typo. That asterisk indicates that daemon is a keyword only argument, and is standard python3 syntax. You can see it if you follow the source link to the threading module.