the scores in the buffer are the ad-hoc score that is used to sort the matches. e.g. consecutive matching chars have exponential score, etc...
re key bindings, it's copied from the docstring of slime-fuzzy-completions-mode:
With focus in *Fuzzy Completions*: Type `n' and `p' (`UP', `DOWN') to navigate between completions. Type `RET' or `TAB' to select the completion near point. Type `q' to abort.
With focus in the target buffer: Type `UP' and `DOWN' to navigate between completions. Type a character that does not constitute a symbol name to insert the current choice and then that character (`(', `)', `SPACE', `RET'.) Use `TAB' to simply insert the current choice. Use C-g to abort.
could this be presented better? e.g. inseting a pointer to this into the top of the completion buffer that can be disabled with customization? is it worth it?