I encountered this a few months ago on my local sandbox (XAMPP). I determined that a CURL error was being tripped when obtaining the current version information from the version server. I'm not remember the exact error (something to do with certificate verification), but installing a cacert.pem file on my computer and adding some information to php.ini solved the problem.
A more detail explanation can be found
here.
The weird string of characters display is the result of the code attempting to extract version information from the curl error string.