A month ago, I wrote a blog on how you can configure the MySQL Shell prompt to suit your
needs. One thing I did not go into details with are the
prompt_256pl+aw.json. Common for both of these
templates is that they require custom fonts to work.
In the two file names, pl stands for the PowerLine fonts and aw for the Awesome font. These fonts add symbols that are useful to create rich prompts, not only for MySQL Shell, but also for Bash, zsh, vim, etc. The symbols include an angle separator, a lock (that in MySQL Shell is used to symbolize an TLS/SSL connection), and so on.